Should I stay with a mate after she or he has cheated on me? (This is not referring to habitual cheaters. That is a different matter.)
This is a very personal choice, and there is no right or wrong answer. If your partner is remorseful and is willing to work it out, I would suggest trying to look at it from this vantage point. My observation has been that when most people cheat, they are trying to solve a problem. They are usually in some kind of emotional trouble or confusion that they believed the cheating would relieve.