Not sure where to go between my ex and my gf?

Basically, my ex and I divorced in January of 07,she got custody of my daughter, remarried within a month, and I moved to another state to clear my head because I didn't believe I could there. It took a while, but finally I managed to heal and get away from the anger and betrayal I had felt. Throughout it all though, I have kept in contact with her and my daughter so I know how my little girl is growing. In december of 07 I met my gf, who for the most part is amazing and makes me happy. Although we were both using protection, in april we found out that we have a baby on the way, due in late december. But, the issue now is because my ex's husband left her, she says that she should have kept me more in my daughters life, and now she is trying to do that, but with my ex and me as platonic friends only, though she has hinted at wanting to get back together again. My gf is of the mind that my ex is playing a game with my head until she finds a new man, and then, I'll be out the door, so to speak. I know part of it, even though she won't admit it, is because of insecurity, and her thinking I want something that I don't. Basically, my gf and me don't even have a relationship anymore because of this. I do care about my ex because she is the mother of my child, and she admitted that she had screwed up, and was truly sorry, but I love my gf with all my heart. I've tried time and time again to reure my gf that I don't want my ex,(which I don't, not at all) but she won't believe me and she keeps pushing me away. Help!! Anyone with serious advice, please help!