Back story : There was DV in my childhood, resulting in broken bones on occasion and father was (is?) an alcoholic who lost his temper at the drop of a hat. I have been NC with him for 9 years. Sibling saw all the violence but 'forgets' it for an easier peaceful life. Parents divorced over a decade ago and both are remarried. My own mother is very 'fogetful' of the past and ignores it all or brushes away any memories or comments of 'it was a long time ago - never mind, we all lived.' 
Now to the present : Sibling is getting married, I was invited to be in the bridal party, I accepted then 24 hours later asked if father was attending, I was told 'Of course.' I then declined, wished them well and said I wouldn't attend. He would purposefully come over to me and start to pull the 'poor me' act, I know I would react and there would be a scene. I don't want him in mine or dc's lives. He's toxic.
I hadn't told extended family about not attending at the time as it was a year ago when they got engaged. Now it's all coming out and I'm being called an attention seeker and 'making it all about me'
I've also been told to put it aside and not miss siblings wedding as it's incredibly selfish of me.
Honestly if he were not attending then I would be going and happy for them on the occasion. I was quite hurt he was invited (especially given that there is never anything positive to say about him) but hey it it's their wedding and their day.
The old MN mantra is ' It's an invite not a summons.' Is going on in my head but I keep having this guilt that as it's a siblings wedding and not a distant cousin I should be attending and my family are right to put the pressure on, but the idea of seeing my father is awful. 