NTA - What I did: My dad married a woman he met, dated, and got engaged to in less than a year after my parents' divorced. Not a bad woman, just too soon. The bachelorette party was on the same day as my best friends birthday so I went to the birthday party instead (which also happened to be my parents' anniversary). Two weeks later I skipped the wedding something that they didn't appreciate and I was told I shouldn't have done, but 20 years later still haven't regretted my decision. Ironically they have since divorced). I told them, I didn't go to Dad's first wedding, I see no reason to go to this one.

My mom remarried 10 years after their divorce. I like the guy, he's really tried to be a great step-dad. They planned a quiet ceremony at a park. I got upset that she didn't even ask the kids to stand with them at the ceremony. The night before they decided that they had been wrong to exclude us and us oldest stood for them and signed as witness. It was stressful (huge fight with my mom) but I'm glad I went and was able to be part of the ceremony.

My advice, do what you need to do for you. You didn't make the decision to cheat on your dad. You didn't decide to marry the guy who tore your family apart. In no way are you TA. Your mom may be mad, but you should not feel obligated to attend. Regardless of what you decide, you are NTA. She may be mad at you, but in no way is it your fault.