Dream of being in love with someone who doesn't love you back

The dream started on the scene where me and my classmates are making a group project. And there is this one guy (also my classmate) who has a nice built body, it seems like he's very sweet and caring and I like him. I keep on making cute faces just to get notice. I can somehow feel that this guy like me before and he notices me, he even smile at me and it gives me butterfly. But I really feel jealous because he's with someone else. He introduce me to his girlfriend a fat but a bit beautiful lady, He kisses her in front of me and it hurts me. when I woke up I can still feel the pain. What do you think this mean? I have a boyfriend in waking life but sometimes I keep on thinking about my ex and how he made me feel when we are still together. I don't want him back I just miss him sometimes.