I cheated on my boyfriend with my abuser
Are you being serious? Why would you cheat with your abuser?
They're good and bad in different ways
Perhaps you were afraid they'd hurt you if you didn't cheat with them? But you shouldn't cheat on your boyfriend, it's not the right thing to do.
I think I should stop talking about it.
You don't have to talk about it with me, but I think you should let your boyfriend know because that's a pretty serious thing. He may want to reconsider the relationship if he knows that you cheated on him.