Im in love with someone who's not in love with me?

I need some help. I've known this guy for a little over a year now and we been seeing each other on and off. I am so in love with him. But i know he's not in love with me. We were close at one point we had our differences and never really completely bounced back afterwords. He stopped answering my calls and my texts. It got to the point to wheres-tho I have to call from different numbers just to get him to pick up. Once he picks up and realize it's me he may talk for a min or two then say he have to go or he's with his kids at the moment and he'll call me back. But of course he never does. I text him every now and then to check on him to see how things are going. He never replies. I feel like my back is up against the wall I tried and done all I can to get it back the way it was. I think he has a baby on the way with his oldest daughters mom. And I kinda figured that's the reason why he just stop talking to me. I been single for about 4yrs now. I am a 21 yr old single mother of one. I have my own place, my own car, have a full time job and I currently attend college . I don't understand it at first I thought it was something I was doing wrong. I really want to be in a relationship and settle down. But I cant seem to get him off my mind. Sometimes I wonder does he think about me as much as I think about him. I tried to get him to come over so i can talk to him face to face but once again he never picks up the phone or replies to my text. What do you guys think I should do?