working through the pain
The question is going to be do you believe that the infidelity is over and that things in the relationship can get better. Even if your boyfriend decides to stay, he is going to have a lot to deal with emotionally. The decision to stay will be so much more painful than a decision to leave. Will you be able to giver him the time and support that he will need from you? The biggest problem in healing from infidelity is processing the pain and many people can't think of anything else. If you are able to handle some of his need to deal with his emotions on his own, than think about what he needs and act accordingly. He may not be ready to be approached about the situation yet. You have to tell him how much you sympathize with his predicament and that you will listen whenever he needs you to. This relationship seems to have a lot of emotional baggage behind it, but if you are willing to put in the effort to make it work than go for it and focus on what he is experiencing. Good luck.