Last Updated on August 21, 2026
Clinically Reviewed by Mrs. Mansi More Nopany
RCI Licensed Clinical Psychologist · M.Phil. Clinical Psychology · PhD Scholar · 10+ Years of Experience
If your boyfriend cheated on you with your best friend, you may not know what to do first.
You might be angry with both of them, checking old conversations for signs you missed, or wondering whether you should leave. And even after what happened, you may still love him or miss your best friend.
There is no single right way to deal with this kind of betrayal. A two-year relationship can look very different from a ten-year relationship where you share a home, money, families, or the same friend circle.
This guide takes you through what to think about first, what information you actually need, and how to decide what happens to both relationships.
Step 1: Let Yourself Feel What Happened
Finding out that someone you love cheated with someone you trusted can bring anger, sadness, embarrassment, jealousy, numbness, and a strong need to do something immediately.
You may want to confront them, post about it, drink too much, revenge cheat, or make them hurt the way you are hurting. Try not to let that first emotional rush create another problem for you.
Cry if you need to, talk to someone you trust, take some distance, and give yourself enough time to think clearly. You do not have to decide in the first few hours whether you will forgive him, leave him, or end the friendship.
Step 2: Understand What Actually Happened
After finding out that your boyfriend cheated with your best friend, you may want every detail. Start with the facts that could actually affect your decision.
Ask yourself what you still need to know:
- Was it emotional, physical, or both?
- Was it one incident or something ongoing?
- When did it start?
- Were they secretly meeting or messaging?
- Had either of them lied when you questioned their closeness?
- Are they telling you the same story?
It is common to go back through chats, photos, dates, trips, and memories trying to work out what you missed.
You may need enough information to understand the betrayal, but you may never get an explanation that makes it feel reasonable. Knowing every sexual detail can also give your mind more painful material to replay without helping you decide what to do.
If either person says the sexual contact was not consensual, do not automatically treat that situation as cheating. That needs to be understood separately.
Step 3: Look at What Is Actually at Stake
Before deciding what happens next, look at what is connected to these relationships in your life.
You may share a home, money, responsibilities, family relationships, pets, work, future plans, or the same group of friends. If the relationship has lasted many years, leaving may involve far more than ending contact with one person.
The friendship also matters. For some women, the boyfriend’s betrayal hurts more because of the romantic, sexual, or practical life they shared. For others, losing the best friend hurts more because she knew their fears, insecurities, and private problems.
You may also discover that mutual friends knew or suspected something. Before assuming everyone betrayed you, try to understand who actually knew what.
No psychologist, friend, or family member can decide what these relationships are worth to you. That part has to come from you.
Step 4: Decide Whether You Even Want to Talk to Them
You can speak to your boyfriend, your best friend, both of them, or neither.
If you want answers, separate conversations may help when the two people are giving different versions. Focus on the main facts: what happened, how long it continued, what was hidden, and whether anything important is still being withheld.
But you do not need a long confrontation before ending either relationship.
If you already know enough, more explanations may simply sound like excuses, minimising, blame-shifting, or attempts to persuade you to stay. You can leave without getting perfect answers or the kind of “closure” you hoped for.
Step 5: Decide Whether You Want to Stay or Leave
This can be the hardest part because love does not disappear automatically when someone cheats.
You may want to leave but worry about throwing away years together. You may still love him while everyone around you is telling you to break up. Or you may be afraid that staying means you have no self-respect.
Try to separate what you actually want from what you think you are supposed to do.
Look at the relationship before the cheating, whether this was one incident or part of a pattern, how much lying was involved, whether he takes responsibility, and what staying or leaving would realistically mean for your life.
Staying does not automatically make you weak. Leaving does not mean the relationship meant nothing.
If your boyfriend and best friend are now together, you may also feel replaced. Their relationship does not prove that yours was fake or that your friend had something you lacked.
If you feel stuck between staying and leaving, relationship counselling can help you think through the decision without making it for you.
Step 6: Look at What He Does After the Cheating Comes Out
If you do not leave immediately, you may start wondering whether he can really change.
Right after being caught, he may cry, apologise, block your friend, share passwords, promise therapy, or become much more attentive. He may also say he was drunk, confused, lonely, or made one terrible mistake.
Listen to the explanation, but look more closely at what happens afterward.
Does he take responsibility without blaming you? Does the hiding stop? Does he respect boundaries? Can he answer difficult questions without becoming angry or dismissive? Does the effort continue after he no longer thinks you are about to leave?
The pattern over time usually tells you more than the intensity of the first apology.
Step 7: Decide What You Would Need If You Stay
Even if he seems genuinely sorry, you may still think, “What if I forgive him and he cheats again?”
The fear may be bigger than another affair. You may worry about losing more years, ignoring another warning sign, or feeling like the biggest fool because you gave him another chance.
If you stay, think about what you would need to feel able to continue: clearer boundaries, honesty about contact, openness when something feels wrong, and behaviour that stays consistent over time.
It becomes especially important if he still wants contact with the friend involved in the cheating. You cannot control who he speaks to, but you can decide what boundaries you are willing to live with.
If you choose to continue the relationship, learning how to rebuild trust after betrayal may be more realistic than expecting yourself to trust him simply because you decided to forgive.
There is no guarantee that someone will never cheat again. You have to decide whether his behaviour gives you enough reason to take that risk.
Step 8: Decide Separately What You Want From Your Best Friend
If your best friend slept with your boyfriend, you do not have to make the same decision about both relationships.
You may stay with him and end the friendship, leave him but eventually repair the friendship, end both relationships, or take distance from both while you decide.
You also do not have to decide who was the “bigger” betrayer. If both knowingly crossed the boundaries of your relationship, both can be responsible for their own choices.
The pain may still feel different. Your boyfriend may have held your romantic and future trust, while your best friend may have known things about you that almost nobody else did.
That is why one of the hardest thoughts can be: “You both knew what would hurt me, and you still did it.”
Step 9: Do Not Turn Their Choices Into a Judgment About Yourself
After cheating, many people begin questioning themselves.
“How did I not see it?”
“Why did I trust them?”
“Was I not enough?”
“Why didn’t I listen to my gut?”
“If I stay, will everyone think I am stupid?”
You may have noticed something and dismissed it because you trusted them. Or there may genuinely have been very little for you to notice.
You can later look honestly at problems in the relationship — arguments, distance, less sex, stress, or communication problems — without turning those problems into responsibility for someone else’s decision to cheat.
Their secrecy does not prove that you were foolish, unattractive, or not enough.
Part of recovery is being able to trust your own judgment again, whether you ultimately stay or leave.
Step 10: Give Yourself Time to Recover
Making a decision does not immediately make the betrayal disappear.
If you stay, you may still check his phone, question delays, worry about female friends, or need repeated reassurance. If you leave, you may still miss him, miss your best friend, compare yourself with her, or replay what happened.
Over time, recovery may look like thinking about the betrayal less often, checking less, sleeping and concentrating better, comparing yourself less, and feeling more confident in your decisions.
If the relationship has ended but you still feel emotionally stuck in what happened, breakup counselling can help you work through the loss and broken trust.
Research involving people who stayed together after infidelity has also identified factors such as reasons for staying, apology, social support, rebuilding trust, and professional help as part of the recovery process. Read the research on PubMed.
Step 11: Get Support If You Keep Going in Circles
Sometimes you know what happened and may even have decided whether to stay or leave, but your mind keeps returning to the same questions.
You may keep replaying the affair, comparing yourself with your friend, checking for new signs, changing your decision, or wondering whether you are staying because you want to or because you are afraid to leave.
Counselling should not simply tell you to leave him or forgive him. It can help you process the betrayal, understand what you want, and make decisions without every choice being driven by anger, fear, humiliation, or pressure from other people.
LeapHope also provides infidelity counselling for people trying to understand what happened, decide what they want next, or work on a relationship after cheating.
Final Thoughts
Finding out that your boyfriend cheated with someone you trusted can affect your relationship, your friendships, and even how much you trust your own judgment.
You do not have to decide everything immediately. Understand what happened, look at what is at stake, decide what information you actually need, and pay attention to behaviour rather than promises.
You may stay, leave, repair one relationship, end both, or take time before deciding. What matters is that the decision becomes yours rather than something driven by revenge, fear, embarrassment, or pressure from other people.
FAQs
Should I forgive my boyfriend for cheating with my best friend?
If your boyfriend cheated on you with your best friend, you do not have to forgive either of them. You know your relationship history, his past efforts, and your own values and boundaries. If you want to forgive and try again, that is your decision. If you want to leave, that is also your decision.
Can a relationship work after he cheats with your best friend?
Yes, it can work, but both people knew they were crossing an important boundary. If you decide to stay together, you will need honesty, accountability, clear boundaries online and socially, no more secrecy, and consistent effort over time. An apology alone is not enough.
What if I still love my boyfriend after he cheated?
If you still love your boyfriend after he cheated, it simply means your feelings did not disappear when you found out. But love is only one part of a relationship. You also need honesty, safety, trust, respect, and a future you feel secure in. Do not ignore what happened just because you still love him.
What if he still wants to be friends with her?
If he cheated with this friend and now wants to continue the relationship with you, be clear about your boundary. Staying closely connected to the person he cheated with makes rebuilding trust very difficult. He can choose that friendship, but you can also choose not to stay in a relationship where it continues.
My boyfriend cheated with my best friend and they are together now. How do I move on?
Yes, it can hurt badly and make you feel replaced, used, or as if both people chose each other over you. But their relationship is not the end of your life. Rebuild your routine, go out, meet people, try new things, and when you feel ready, date someone whose values and behaviour match what you want from a relationship.
