Why do guys play mind games?

I got dumped by my ex. He's been continuing to harass me for the past few months. He doesn't want to be with me thought he says but wants me without a title. We ended up sleeping together after being broken up but he still didn't want to be with me and I thought I twas because he wanted to date around but I found out it isn't that reason. It kills me because he has broken up with me and begged for me back so many times promising me that he wouldn't do this again but he did it for good and its been 3 months. I don't know what he wants from me and why he doesn't want to let go and continues to call me and want to see me. I feel like I couldn't get over him at all because he kept trying to keep in contact and now I'm suffering and angry because I feel like I got screwed over again and I can't get over him because he won't let me. Why is he doing this to me? Why do guys play with girls minds so much? And why do they want control? I don't feel like I did anything wrong to deserve getting dump nor do I deserve him not letting me go. I decided not to pick up his phone calls anymore but I lied and said ill call him in a few weeks but I'm not. I just want to get over I'm now. Help?