Sounds like this is a no brainer to me. I’m a step parent to a brilliant kid who’s father is a complete narcissist, and I’ll tell you this, if a parent tells you to dislike the other parent, don’t trust them without evidence. Make your own decision, and listen to the parent that let’s you make it. A caveat is that a better parent probably won’t tell you all of the bad things they’ve had to deal with, and it’s important to remember that everyone is human and makes mistakes.

It’s ok to have a relationship with both parents, and it sounds like you know which parent to trust. That doesn’t mean you need to cut your mom out of your life, you just get to have a different kind of relationship with her. I’m a fan of honesty, if either parent does something you don’t like, tell them so and ask them to stop. If they won’t, you’ve got a real good answer as to who you want to spend your time with.