<human>: Can you give me the gist of the text in a nutshell?

So, like most TIFU'S, this happened a couple of weeks ago but is still ongoing. So Last year I was told by my dad that my cousin (We will call him richard) was getting married in spring. Me and my sister were not given an invitation but instead, a card from hallmark was sent to my dad's house with; me, my sister's name my dad and his girlfriend. Me and my sister were having reservations about the event because we don't like that side of the family. They have never been for me and my sis during our difficult childhood and never contacted us or speak to us directly only by proxy through our dad. Anyway fast forward to a couple of weeks ago. I call up by dad to ask how he is and he reminds me that richard's wedding is next week, on the same day of the six nations final. I already made plans with my best friend from university to meet up in town to watch it and drink heavily. I said honestly to my dad, that me and richard never got along and I don't see why I should go, as well as that side of the family haven't spoken to me or my sister in years and haven't bothered to reach out. So after the wedding, I call up my dad and know he hates me and tells me off everytime it comes up. The entire side of his family blames my mother and curse my name and my sister. So I don't know what to do. On one hand at least it has saved me from writing christmas cards for that side of the family, but on the other hand I don't know what do to with my dad.
<bot>: refused to go to my cousins wedding on the grounds that I didn't like him and I wanted to go watch the six nations in a Irish pub, and now my dad and his side of the family hates me and my sister.