He is so hot and cold with me, and I don't know what to do?

Me and my ex boyfriend have kept in contact ever since the split, 2 years ago.

We have slept together quite a few times in the past, and once within the last 2 months. We're both at uni so we don't see each other often but he always talk to me, IM's, texts me and sometimes calls me. He went through a faze of texting me every single time he was drunk but he hasn't done that recently.

He randomly text me yesterday a movie quote from one of my favorite movies which I thought was really random as we haven't spoke in a week (which is unusual for us). I just have no idea what's going on, and I'm major confused about what's he's feeling towards me.