Advice?

I've been talking to this guy for almost a month now and I just found out that hes been saying really mean things about me behind my back. I blow up his phone and he doesn't really want to talk to me, etc. I was planning I having sex with him and now I feel really betrayed. Apparently he told one of my really good friends, my cousin and my sister who didn't even tell me about what was going on. Now I have no idea what to do