What do you do when you let the love of your life go and then miss him so much you can't live without him?

Ok, well I started to date this guy. I really didn't know if I liked him or not at first, but then when I got to know him I could feel myself falling in love with him and it scared the hell out of me. So we went out one night and his x, which is his first love, kept texting him begging him to come back. When he took me home I texted him and told him that I thought that he should go back to his x. So he did. Now we have been talking more than ever and I realize now that the only reason that I told him to go was because I was falling for him and I was scared that he would break my heart by going back to her anyway. He says he misses me to and that he doesn't wanta hurt her because he just got back together with her, but he really likes my too. So what do I do? I am really in love with him and cant' emagine my life without him.