Most Helpful Guy
For starters, yes, guys do, in fact, get jealous.
But here's a couple things you need to learn, right here and now.
For starters, it might be possible to get him back, but jealousy is NOT a good idea, and NOT a good way to go about it. Chances are you're more likely to tick him off, or think "I wouldn't want her now, anymore, anyway." which doesn't help you. But thing is, yes, it is possible that jealous would make him come back, but not only is it slim-to-none chances, but there's another lesson you need to learn about it.
Jealousy is not a good thing. Even if you did get him back through this method, it's not because he loves you. It's not because he cares about you. Jealousy isn't about love or caring. It's about control, possession, territoriality, insecurity, and all things bad. So getting him bad would be a hollow victory, because it wouldn't mean he actually cares about you. He's just territorial and possessive.
Furthermore, I want you to think about these next bunch of questions, really hard.
Say you did get him back with jealousy. What then? The next time things go bad, what are you going to do? Pull some stupid jealousy stunt again? Should you really have to screw with his head to keep him? Is that the kind of relationship you want?
Worse yet, the guy you're messing with to make him jealous is being completely used, and toyed with. Do you care about that guy's feelings at all? Did you even consider that?
What about your ex boyfriend? You said he's in a new relationship. Are you really so selfish that you want to destroy the relationship he has just to get him back?
Look, you said it yourself, your relationship went to hell because you kept fighting and his feelings changed. Your relationship is over. He's moved on. Maybe you should too. You're already dating around; so how about you actually date good guys you actually like? Y'know, instead of just guys, you're flatout using to fill a void, and make your ex jealous. If you can't find someone you genuinely like, maybe you should work on being happy by yourself, before you rebound any further.
But whenever you DO find someone, use your past relationship as a learning experience. All those stupid things that killed your last relationship? Learn from them. Don't make the same mistakes you did the last time.
I want you to think hard on everything I just said. I'm serious, this is stuff you NEED to learn, and quick. Nothing good will come from what you've asked about. Don't even try. Just move on, and leave your ex alone. Seriously.