What the hell is with your questions, lady? Leave the damn bastard and call the police ffs. You should never forgive someone who hurts you or your unborn child, or hurts your trust like that. What. The. Hell.
Good. Stay away from him. Because jeeze.. all these questions you're asking should come down to common sense. That's it. You should've left the first time he brought home an STD, or at the first sign he'd become abusive. And next time.. wear a condom with the person until you know damn sure they don't turn out the same and you end up pregnant or having a child with an abusive / unstable *******.
I would have a hard time forgiveing him. I would eventualy but I wouldn't stay with him.
#1 I wouldn't ever forgive him for cheating. #2 How did he cause you to miscarry? Unless he physically hurt you, like threw you down the stairs or something, I don't think arguing will cause a miscarriage. But if he hurt you, you should call the police. Otherwise: Leave him for cheating and stop being so dramatic!
Stress from arguing can indeed cause a miscarriage, but this sounds like straight up physical abuse. ( I could be wrong, but either way. )
Hell no, get away from him.