Just sort of apologize like you really mean it. And if he refuses that's a loss for him.
See if he has changed for the better. If not, stay away from him.
how do you know if your boyfriend has cheated
Sounds like you need a better boyfriend.
Next Boyfriend....
tell her that her boyfriend cheated on her. she needs to know.
If it is so obvious to your boyfriend then have 'him' prove it. He should get his facts straight before he accuses you of cheating. Let him do the leg work and you know the truth and tell him so.
Dump him
you go and tell him you cheated on him and tell him how sorry you are and ask him to forgive you.
You can't prove that.
There is no way to positively know if your boyfriend has cheated on you unless you catch him or he tells you. There may be some signs such as not being where he says he is or lying to you on who he was with.
break up with him
yes. Why...?