What is he doing ex boyfriend troubles?

My ex boyfriend and I broke up 9 months ago, we dated for almost three years. He's been dating this new girl for about two months now. Two weeks before they were dating he was texting me on a nightly basis. Once they started dating he stoped calling, after about three weeks of not hearing from him he texted. From that point on he's called me just about every weekend seeing what I'm up too, he's asked me to come over and have too. On the very select few times that I do decide to text him it's 50.50 if i'm going to hear from him .I haven't slept with my ex for about seven months now but he still keeps calling. Why is he messing with me?