What to think of him?

So I went home this weekend for Thanksgiving break and to watch football with my family. We on friday my sister had a Variety Show, so my friends and I went to watch her and old some friends from high school. Well I knew that my ex would be there, so I made sure that I looked really good so when he saw me would be like “damn.” Anyways, he saw me and looked at me, but didn’t say anything. Well later during the show he calls me to ask me a question, but I didn’t hear it go off. So I waited til after the show to call him, and he didn’t answer. See he hasn’t called me in 2 months, so I was wondering why. Anyways, I go to his football game and my brother’s game to cheer them on. Well his girlfriend was there and stood right behind and started talking bad about me. Anyways my ex’s grandpa comes up to me and hugs me and talks to me and doesn’t even say hi to her. So I started to laugh about that.

 Then after saturday went by, I decided on Sunday I would call my ex one more time to see what he really wanted.  Well he didn't answer, so I said just forget it.  Well later he got on the internet and talked to me for 1 hour about everything known to man.  We talked about his football career in high school, my family and his family.  We talked about many other things.  And he was actually really nice to me and wanted to talk.  Well I told him I was coming back to the high school during my THanksgivng break because I was observing some teachers and he said that was cool and things like that.  So I guess what I am trying to ask is, what does this all mean?  I mean for two weeks now his family has told me that they don't like his girlfriend and that he shouldn't be with her.  And now is talking to me again out of the blues.  So does that mean he is going to break up with her, or does he just want to talk?  And I am also nevrous going back to high school because if they are together she will be so mean to me and be all over him, so what do I do and how do I act around them?