Growing animosity towards my mother?

My Mom has been seeing this guy off and on for about 7 months now, let's call him John. I really dislike this guy, because he began cheating on his Wife with my Mother. Seeing as my Mother and his Wife were really good friends before, it repulsed me that my own Mom would commit such a repugnant and backstabbing act. It doesn't help that John has also lied to my Mother countless times about various things, only to manipulate her into giving him another chance because he tells her what she wants to hear. It's utterly pathetic.

Now onto specifics:

They have really loud sex almost every night that he comes over. He tries to be buddy buddy with me when he notices how frustrated his being here makes me. Honestly, I don't really have any interest in being civil with this guy. I don't think I have it in me to warm up to someone who is such a douchebag on so many levels.

I'm 17 (Turn 18 in January), and I've really been considering moving out shortly after my Birthday. I don't know if this is the best way to tell my Mom that I'm disgusted with her and how much of a low priority she's made me as of late, but I don't see any other options for me.