SOMEONE HELP ME?!!!

My ex and I have been talking recently. We have been sleeping together on and off for 4 years.. And had a relationship for a year and we got engaged. I made a huge mistake and I left him. He got a new girlfriend and they have recently broken up. So we started talking before they did and he said that he's not looking for a relationship with anyone needs to have time to himself. This isnt a problem though... The problem is that when we meet up we act like a couple still. Laughing hugging kissing joking about and of course having sex. I got pregnant during our breakup (no longer in contact with the dad) and so this is making it very difficult for me as I want to be with my ex so bad. He comes to me with everything and is always up for hanging out and talking to me. I feel like he still has feelings for me but just doesn't want to admit that he does. It's breaking my heart. He's told me that he misses me and our relationship but that he's only interested in me as a friend who he sleeps with. A fuck buddy essentially. How do I win him round? Or do I just have to be patient?. I really love him and want to be with him. I'm so confused with all of this. One minute it's as though he wants me... The next he doesn't. Someone help?!