Devastated

So I find out some very disturbing news today. My dad has been cheating on my step mom for 8 years. The worst part is it is with the same woman that ruined his life 20 years ago. I find out that he can't decide who he want to be with. I decided if he chooses the other woman he is no longer in my life. He chose my step mom which is the best decison he could have made. It just pissed me off so bad to see him throw away his life again. I love my dad but he has hurt me a lot in my life. I am glad he did he right thing and I hope he doesn't mess up again.