Why has my ex boyfriend got a girlfriend only a couple of weeks after he dumped me????? ADVICE PLEASE!!!!!!!!!?

[Amy]

I met a guy on a dating site in June who I started dating... He was coming up to a study period and asked me out at the beginning of it. Since we were in a relationship, I texted him etc during this period and he really liked me to begin with but he started disliking the fact I was trying to talk to him throughout this month (even though he was meant to be my boyfriend). After the study period ended, I went to see him and he was rude to me and made no effort to be a good boyfriend/make up for all the time I had waited around for him.

From then on he begun dumping me and asking for me back, each time he said we could work it out. But the longer it went on, he started being more rude. In the end he dumped me for good and said he really, really disliked me and that he thought I was not pretty etc. (This was about 3 weeks ago).

The other day he told me hes already got a new girlfriend and that I should never speak to him again/that he really hated me. I mean I had noticed that towards the end he had been using the dating site alot that we met on. But he said this new girlfriend he met in a restaruant (I think he met her on the site). I thought he was lying and he said he really REALLY likes her. He says they met recently and he asked her out (the same he did to me). I've just seen he has got a picture of him and her IN HIS ROOM as his facebook profile picture (he took one in the same pose of me and him when we started dating URGH). He never had a picture of us as his profile picture.. Anyway the girlfriend is real. I'm really mad that he must have started seeing her when he was still asking to see me (a couple of weeks ago) because he was saying to me we can be friends/I will take you for a nice meal.

Is he going to do the same to her as he did to me? Hes lovely to begin with but then turns really picky and even admitted to me he has a short temper. Why has he asked her out after a couple of weeks like he did with me? Is he completely desperate for a girlfriend?