My boyfriend is ignoring me and being an butthole

what do I do, My boyfriend is ignoring me and being an butthole.
before me and him got back together he promised he would sit with me and lunch and everything and he doesnt and when I am with my friends in a conversation at lunch he comes up and says...

the stupidest things or starts being a smartass to them. he even pushes my sister out of the way when she is beside me so he can get to her.
What do I do?

This is usually why ex's shouldnt get back together. It very seldom ever works the second time around once the relationship ended. You two broke up for a reason, and its obvious by his actions that he doesnt care the least bit about you. What do you do? You end it, and this time for good! Dating is a process of weeding out the bad, and keeping the one who treats you with respect, loves you, and shows you by his actions!

dont take that crap from him--break up w/him.

and if he pushes your sister again, kick his butt in front of everyone!