Whatt do i doo? Pleasee help!?

Ohkayy, i have this boy who is my exboyfriend. we dated once and he broke up with me. he dated 2 girls that week we were broke up and he came back to me and asked me back outt. i saidd yess and we dated for another week and he broke up with me again. :( i still lovve him with everything! i would give him the world! but he has a girlfriend?! i dont know what to do!? i cant get over him, i am in love with him. If for some reason he comes back to mee, what do i do? please answerr thiss!