Cousin's wedding & very difficult family? What should I do?

Id say that you should go to the wedding just so you can be there for your cousin. Also to see other family members that you miss. You aunt should be on her best behaviour as its a wedding and she shouldn't want to spoil her daughters day. If she does talk to you at the wedding and you get disapproving looks when you say about your personal situation, make your excuses to leave the conversation (in a polite way) and talk to someone else who isn't as disapproving..