The betrayal of a loved one very much hurts, perhaps, any person. He feels deceived, betrayed, insulted, he can no longer trust his partner. But if the guilty party sincerely regrets what they did, you can try to maintain the relationship.
Think about what could have prompted your partner to cheat. Perhaps there are serious problems in your union, since he needed new sensations. Analyze the events of the last days, weeks, months: whether there have been conflicts, misunderstandings between you, whether something has changed in your relationship.
Discuss what happened with your loved one, listen carefully and make it clear that although he hurt you deep in your heart with his act, you are ready to forgive him, but this will take time.
Evaluate the situation from the following position: you have been together for quite a long time, during this time you have experienced a lot of good and bad, were with each other in happiness and sorrow, coped with difficulties and enjoyed pleasant moments. Consider whether cheating outweighs this shared life experience.
If you and your partner are determined to stay in touch, try to treat cheating as just another nuisance that you have overcome and not think about it in the future. It may not be easy, but learn to trust each other again.
Not everyone is able to independently cope with the betrayal of a loved one. In this case, a psychotherapist will come to the rescue: contact him first separately, then together. In the West, this practice is widespread, while in Russia it is taking root, but it gives good results, just find a competent specialist.
Do not take what happened to the judgment of relatives, friends, acquaintances, colleagues at work: this applies only to the two of you, so only together you can make the right decision about how to live further. If you have children, do not interfere with them in the showdown and do not manipulate them in your own interests.
Try to live separately from each other for a while and not meet. So you can symbolically end the life stage that ended in betrayal, turn the page, and then start the relationship from scratch: make dates, give gifts and build a new life together.