My 21 y/o cousin is getting married to her 20 y/o bf tomorrow. They've been together for almost three years and during that time, he cheated on her at least 3 times that I know of. The most recent one just a few months ago. But that's no why I'm having a hard time deciding whether or not to go.

Since getting engaged, cousin has tried to cut her family out. Her dad(my uncle) is not even invited to the wedding! She wrote him a nasty letter, insulting him and telling him he's not welcomed to her wedding when he cautioned her against marrying this guy. Everyone in the family has told cousin to apologize to her dad and invite him to the wedding because if she doesn't she will regret it.

I heard about cousin's engagement through my mom who got a facebook invite two months ago. Cousin used to call and text me all the time but then just stopped ever since her fight with her dad (BTW, I'm not my uncle's biggest fan nor do I agree with how he does things but still in this case I think he's right).

My mother is staying with us temporarely and two weeks ago cousin and her bf came to visit my mom at my house. While talking about the wedding, my mom commented on how she's the only one in the room who is invited to the wedding. Cousin said they're running behind on sending out invitations but will send one out to me and DH. We got the invite in the mail last Saturday (a week before the wedding). I already made plans for tomorrow and DH already has plans with the kids. My mom is trying to convince me to go to either the ceremony or the reception. I explained to her that I'm not going to go, I was invited solely because my mom pressured her.

Cousin asked my mom to help her tomorrow get her wedding dress on. Cousin asked my mom to cook for the reception because my aunt(cousin's mom) refused to cook since cousin has been so disrespectful and rude to her and the rest of the family. My mom agreed but mom has been unemployed for a few months and doesn't have the money. So DH took her to Costco and helped her purchase enough food to feed the 40 people cousin invited to her wedding. I feel like that's enough contribution on our part, and DH and I shouldn't spend more money on gifts. The food is our gift to her. I'm also not wiling to cancel my plan tomorrow or make my husband cancel his plans with the kids to go to a wedding for someone who is ungrateful and doesn't even consider me a family.

Am I being heartless here? Please be honest, I'm a big girl, I can take it