A story as old as time. My father cheated on my mom for five years with a younger woman, and he left my mom when the mistress got pregnant. It tore our family apart. I resent my father because my mother actually loved him, and she's still dealing with this, even a year after he left her. I stayed on okay terms with him because I was the one to pick up and drop off my younger brother at his place. Last week, when I picked up my brother, my father had big news. He proposed to his girlfriend and wanted me to be his best woman. It made me kind of mad, I'm not going to lie, but I kept calm. And I told him no. He said what happened between him and my mom was none of our business and that I should respect his new relationship. I said I respect it, but that doesn't mean I can don't it. Obviously, I would never hound him randomly about it, but I don't approve of it and I don't like her. She knew the whole time, mom, and we existed. Well, my dad was having none of this and told me to get off my high horse because I had cheated too and I had no right. And I guess when I was younger, I was with this boy for three months. I went to a party got shit face made out with his classmate for a total of 10 minutes. I felt so bad that I called my boyfriend crying and we talked it out. We broke up. I told my dad about 10 years ago, I never did something like that again. I've been with my partner for five years. I told him he could not equate it at all. He called me a hypocrite and that he was glad to know who I am. Driving home, I felt like I was a bit harsh. He's still my father, but he's not a bad dad. I just don't want to be in his wedding. I would still go, but am I the asshole?

You are definitely not the asshole.