Why am I so jealous?

This guy who I liked for a while has this new girlfriend who's a year younger than us. Before he went out with her, he was telling me that he had his eyes on a new girl, though I suspect it turned out that he went out with the girl. Anyways, the thing is that him and I had a fling many, many months ago, but for some reason, it comes back to my mind. He also had this obsession with getting his hands on me, where he persuaded me millions of times to have sex with him, but I couldn't give in since we weren't going out, I thought I was too young, and I wasn't ready, but this whole chananigan continued for months!

So, I mean everytime I see them, holding hands and so forth, I get so jealous! I mean, I feel like my jealous streak shows so much, but I don't want him to think that. I mean, I'm happy for him and all, but there's a part of me that still can't let go. At most times, he was rude and a total jerk to me who wanted to get laid. Many believe he's just going out with this girl because he wants to get laid and that's it. I remember I was planning to stay after school for a class, which he walked into with his girlfriend, but the minute I saw them, I walked out.

I can't take it anymore, meaning the jealousy I have. I have no idea what to do? What do you think I should do?

Wow, that guy sounds like a real jerk to me!
I feel your pain though!
It's like, you've had history with this guy and it's pretty much being shoved in your face that he's having the same intentions for this new girl.

To me, he doesn't sound like a true guyfriend and is seriously just a horndog.
You don't need him.

I say just back away from the situation and occupy yourself with others things other than them being together.
I know it's hard but try to be happy for the girl.
Atleast you don't have a airheaded as*h*le as a boyfriend.

There are WAAAY more and I mean WAY more guys out there that will respect you and not try to pressure you into sexual favors.

Ditch him.
Both of them are so not worth your time.

It's natural be to jealous! Of cousre you would be if you liked/(loved?) him at one point!
Best thing to do is, not walk out of the room to say Hi or somthing, make it appear that you are OK with it, I know your not, but if you REALLY appear that you are, that will get him thinking 'Why is she suddly over me? Why doesn't she want me?' Ect. He will suddly be talking to you again, just be like well I'm AMAZING thanks then walk off.
He will feel like S*it that he hasn't been the person to make you happy. Many thoughts will go though his head and make him jealous just like you, and by hopfuly that time his and his gril friend have broken up because if all he wants is sex then the relasiontionship never works, even if she's a wh*re xx - Hope this helped -