Should I deal with my demon and go to this wedding?

I was sexually abused by my ex-stepdad for years when I was a kid.. I'm in my early 30's now and have not had any contact with him in about 13 years or so (other than seeing him shopping at my workplace a few times or a couple random awkward moments when he was visiting my half-sisters). Only my girlfriend and a few close friends know about this. Anyway his niece, whom I consider my cousin, is getting married in a few months and I really want to attend her wedding.. BUT I am pretty sure I will be seated at the same table as him.. And I would not know how to handle that situation. Do I just smile and act normal.. be cordial?? (to this man who had destroyed me).. Do I just not go altogether? Any serious advice is greatly appreciated.. This is weighing heavily on my heart right now. Thank you.