Whats his problem??

When i first started to this boy, he told me that his ex wouldnt leave him alone and that she wanted him back. He always called her a ***** and stuff. Well his ex had dumped him for another and guy and also cheated on him. Well, we were talking for about a month when he gets mad at me and quits speaking to me. A month later we start back talking again and it was like he was a different person! Basically a jerk, he told me that he didnt want a gf and i liked him so much.But i took that as i want some. I felt like i was backed into a corner so agreed to a fwb with him but we didnt do anything cause i backed out and im a virgin! So of course he slowly disappears from my life. Well, i just found out that he was telling lies about me to his friends saying that i called him all time,when he was the one who texting me and riding past my job looking at me. he also said we had and i became clingy!! It just came to me that he talked about his ex basically the same way! Whats his problem?