Ex boyfriend

I just kinda wanted to rant a little so I'm sorry. So I have this ex. He cheated on me and went back to his ex-fiancé after a year of us being together. It's been about six months. He has people I thought were my friends stalking my social media for posts about him. I made a post saying how I wish he had been a complete horrible person. I have so many good memories with him and that's what hurts more than anything. If he had been a completely horrible person, it wouldn't be so hard to let go. Well anyways I posted that. I was feeling sad and looked at his blog. He had a post up that said "if you're seeing this, you're still not over me. Lol pathetic!!!" I commented on it and said "Yeah. You're right. I'm not. Does that make you feel like a bigger man? Did your dick just grow??" He made another post calling me a whore and saying he wouldn't have cheated if I wasn't out flirting with every guy who paid attention to me and opening my legs for them. Now I'm frustrated. I had never flirted with anyone while I was with him. I had never had sex with anyone while we were together. I loved him and had plans to marry him. So I don't know who he's talking about. I'm really angry over this. He's throwing all of these insults and accusations at me. Meanwhile HE'S THE ONE WHO CHEATED. I don't know what I'm supposed to do..