Well, this is going to take alot of text.
You probably won't listen to it, as most teenagers don't listen to advice, but I'm going to throw in my 4 cents anyway!
Whoever this boy is, if he was dumb enough to leave you, he obviously isn't worth your time. Sometimes relationships work, sometimes they don't. Sometimes they go insanely well, and other times they soar downhill. It's unavoidable (that is if you enjoy dating!).
Well, I suggest that first off, if your heart isn't into the boy you're dating now, you should break up with him. Because you never know, he could be seriously crushing you, and could fall in love, and you'd have no idea, if you weren't really paying attention. You also shouldn't date this boy because you want the other boy to be jealous, break up with his current girlfriend, and go back to you.
That rarely, if ever, works. Maybe it's best that you don't date for a while. I hate to sound like a mother, but I'm not saying any lies am I?
If the boy you still like broke your heart- it's best not to get into a relationship with him again, because if he broke it once, he's likely to break it again. If he really does love you, he will let you know in a certain way that no one can really explain. I hope I helped!
*IceMountain®©