Relationship Help !!?

idont know wht to do with this guy i really like , ......... we used to talk all day 24/7 for like a month ....we both hooked up and i have a boyfriend but he knew and he would always ask me if im still with him... and i could tell he really liked me and he told me himseelf . then little by little he talked to me less and less and now we dont talk at all and at school i feel embareased to talk to him cause i feel like im bother him or something ... and he has a girlfriend now and they seem really happy. i get jealous ween theyre both together. i really miss him .i feel lost and not myself with out him and despressed. everyone tells me that me and him make a great couple and everyone wanted us to gether , what should i do ? should i forget him and let him be happy or should i talk to him and be friends ? pls hellppp i really need ADVICE AND TIPS !!!!! (btw Im a Gemini Female and he is a Capricorn Male )