I made a huge mistake...need advice asap!!

My ex and I broke up sometime ago but we still talk and hang out and act like we are still together or that's just the impression I get...well he has a girlfriend and I know I shouldn't but we had sex...it just seemed like he was saying all the right things to me...we tried to work it out but I just wasnt ready but now I want to and he has a girlfriend...I mean he made mistakes and I could have been a better girlfriend but when ever it's just him and I everything seems so right...I basacilly lose track of time when I'm with him...I told him that we should be together because if two people love each other then we can be together no questions asked but he said it's not that simple and to make matters worst he was my 1st...he said that he wants to be with me but he needs to give her time...is this just his excuse not to be with me and just to have sex...I really need help on this how should I approach him and ask him what we need to do or say or something please help

Personally I dont believe in love. But let's pretend I do. Well if you move on then you'll notice everything you didnt. You'll notice that a lot of things will start to remind you of him. And then one day you'll go back an have sex with him. THEN AGAIN AND AGAIN AND AGAIN, thinking that mabye if it is love and you two are having sex, he'll leave the other girl. But the sad truth is he won't. Because if he really so called "loved you" why would he even be wasting his time with the other girl

DOnt listen to the person above me. People break up over juvinile things, where they could have just discussed it or worked it out. The truth probably is that you two should have never broken up, over something so stupid, and love doesn't just dissapear. It's still there. He's just trying to go on and continue his life, but he can't just let you go, and either can you. Tell him you love him in a personal atmosphere and time, and see how he reacts. Tell him you want him back.

well like 3 days after we had sex...at school he didn't say anything but hey to me...and we talked the night before but it wasn't very long...then I met up with him at my church and we just had a normal convo but it didn't last long because his mom came...but he was holding me in his arms so I'm so confused on what to do...oh yeah he told me but I agreed that we wouldn't have sex again...I still like him but I need to move on but don't know what to do????