I'm trying to convince myself I'm over him......

My boyfriend and I got together on February 24th,2010 and Broke up with me on August 26th,2010.
We had a good relationship for the first 4 months, then the last 2 months just totally broke me apart and then came the day he finally broke up with me.
I totally took care of him and all his needs and he took care of me financially, we were cute together and good together.
Well He started a job where he works out in a field and that's when everything went downhill so fast and I tried so hard to avoid it.
I had the feeling he was cheating on me with his so called co-worker and I kept confronting him about it and he would deny it and deny it saying he would never screw her again and never want to.....(his co-worker was also his ex)
On the 25th he was home but didn't come to bed with me and she was at the house, he slept with her with me around..... So on the 26th I pulled him aside for the final time and asked what was going on, he then said there was no more reason to beat around the bush and that he would rather be with her.
This just so happens to be the 10th guy I have had cheat on me and leave me for a specific type of girl, a blond......
I thought I was getting over him but then he showed back up at the house today with her....(he moved out to live with her in her dad's basement) and now I'm thinking about all the unanswered questions I have for him and how he's better off with me cause damn he looked like hell.
He never looked that bad when he was with me and now I'm just blah and depressed trying to figure out what to do cause I've been trying to convince myself that I'm over him but now it seems as though I may not be no matter how much I try to convince myself......

Anybody have any advice to help heal my broken heart.....I truly loved this man! and still do!!!!!