Stupid ex

Really starting to get sick of having to see my ex virtually every day.
He's on the same university course as me, so every time I go to a lecture he's there.
Usually he's already sat in his seat near the front, and I have to walk across the front of the room and go past him to get to where I like to sit at the back. I try to ignore him and pretend I can't see him so I've managed to avoid making any kind of eye contact for a good few weeks. But when I'm sat down I can see his stupid fat head at the front of the class and it's just so IRRITATING!
Any feelings I ever had for him have just turned to hate.
Getting with him was the biggest mistake I've ever made.
In two weeks it will be a year since that fateful night when we first hooked up. I'm so ashamed thinking of it now, it wasn't at all how I thought it would go down. I was absolutely off my face drunk and there are big chunks of that night I still don't remember. How I let that turn into a six month relationship is beyond me, thinking about it just makes me angry at myself. Was I that desperate for a boyfriend that I was willing to put up with HIM?
We were 'fuck buddies' for ages because he didn't want a girlfriend, and I just went along with it because I had no idea what I was doing. I didn't really want to be in a relationship with him, but I hated being treated like a dirty little secret. All he ever talked about was whether any of my flat mates had twigged what was happening... Looking back now I have no idea why I did it because I don't find him attractive at all. I'm not saying that I'm good looking, but he wasn't pushing any buttons for me. The whole thing just makes me feel really stupid, and having to see him all the time is a constant reminder of how badly I screwed up.