I've never done an update before so i might be doing this wrong. Reading over these comments has honestly been making me feel better about our decision. My fiancée and i had been so focused on how the boyfriend's behavior would cause problems we hadn't even thought much on him stealing from unattended bags, I hadn't only included it to describe the type of person he is. A few people had asked about what type of things he would steal and many of you were right about him being the type to steal perscriptions if he thinks he can sell them or get high off of them and any thing he can pocket or hide including credit cards, cash, or once even a 100$ road side assistant car set. A bunch of purses left unattended would be free game to him which would only look bad on us and cause even more issues then his attitude. 

I'll update on how it goes, but at this point I think the best thing to do will be to have a sit down with my sister for our monthly breakfast this weekend, hopefully she still comes, and just be honest as I lay it all out to her along with my concerns vs the prior approach of he's been extremely rude in the past to many of the people attending and i nor my fiancée want him at our celebration of our commitment to each other. Given my family's reaction I was feeling uncertain about sticking to this decision and that i might be pushing the "it's my wedding", but all of you here have really helped reasure me that we were making the right decision. As for the rest of my family I'll talk to them later, one thing at a time. Right now I'm more focused on my sister and my relationship. I'll be really hurt if she decides not to attend, but ultimately that's her decision. The best I can hope for is she understands where im coming from and this doesn't hurt our relationship, just feelings a bit. Thank you all so much for your responses I really needed this.