If your dad says he loves you, I’m guessing you can talk with him. You haven’t mentioned dad being violent, and that’s a good thing. So why don’t you ask him to please stop calling your mother names? Tell him how it makes you feel, and that you believe mom deserves to be treated with respect.
It is not really your responsibility to get involved in the ‘cheating’ issue, but I guess you could ask him if he’s ever cheated on your mom if you want to. Just be prepared for him to be a bit outraged by the question. You could say kids at school talk about that kind of thing.
I’m not sure how you ‘know’ he's been cheating, or why your mother hasn’t addressed it, so perhaps he hasn’t in the true sense of the word.
Instead of instantly hating your father, I think you should try to get to know him better and discuss the issues that bother you.