Why has he suddenly started being horrible to me/blocked me?

I was seeing this french guy for a month a little while ago. He basically ditched me for another girl, and then his thai friend started showing interest in me.. this was about a month ago and we met up a few times/he stayed over. He didn't actually make any effort to speak to me when he came round, he just went on the computer and ignored me, but would only make an effort in bed. I went home over easter and he kept texting me like please come back early, please I miss you (he texted me it all the time) I just saw him the other day, and I really didn't want to sleep with him but I thought ok I will. I had been holding off for a long time. The next morning he left quite early and said what are you doing today? text me later if you are around in town. I was annoyed he just wanted to leave and so I asked if he enjoyed the he said no 'it was f*ked up' and so I said I don't want to meet you again. Later he texted me from his friends phone being ok, and we had apologised to each other, then today he texted me saying I don't want to see you again. Seriously leave me alone and to not text him. Then he said why don't you go and meet Lucas instead of me. (Lucas is the french guy/his friend that I'd been seeing before) he hated it whenever I mentioned lucas's name. I don't know what his issues are with me, did he just want and that was it? his friend was texting me earlier and he said he had told him I slept with Lucas. Is this a big issue for him????