Please help. I'm desperate.

My ex & I broke up. I broke up with him. Mainly because our whole relationship consisted of a pattern of really bad fights, but also such intense passion & love that was always hard to give up on. At his core he's a person I'm completely in love with & I know his potential exceeds that of the majority of guys I've met. But he's done some pretty stupid things & he started getting really disrespectful and inconsistent to the point that it wasn't worth it for me anymore.

He begged & begged for me back - saying he wanted to be the guy to treat me like a princess, that things could be so different & that he was SO insanely sorry for the way he treated me. I agreed to meet up to discuss the idea of it & things went well. We hooked up, but didn't officially decide to get back together yet. He told me he loved me & wanted to be with me. We talked about meeting up later, after hanging out with friends. It was his idea. He talked about it all night. Said he couldn't even talk to another girl because his heart was with me.

Well, later, he blew me off. Got wasted. Completely ditched me. And HAD SEX WITH ANOTHER GIRL.

A week later, he confronted me and told me everything. Said it made him realize how special I was and how much he truly wanted to be with me. He's been begging for me back for about a month now. Writing notes, texts, emails, leaving flowers, voicemails, you name it.

At my core I still love him to death & I know he is genuinely sorry, but he hurt me so badly. His actions didn't back up his words. He chose to have sex with another girl over spending time/hooking up with me. This is a guy I thought I was going to marry! I truly did. He's the first guy I met who has had all the qualities I've ever wanted in a life long partner. And now, the way he is talking, he actually wants to BE that guy. For the first time ever. And it's all I've wanted for SO long- was for him to be consistent & he finally is but he hurt me so badly and I'm not sure I can get past it. Or how.

IDK what to do. My heart says yes, my head says you're an idiot. Help. : (