How do I win my baby's father back?

We were together for nearly 6 years, and had many ups and downs throughout. We are both 34 and had a child from a previous relationship.In 2008, we had our 1st daughter together, and it was a wonderful year. However, close to the time she was to turn 1, we were not getting along, as his son had made false allegations to his mother during one of his visits with her and CPS was called, and I was mortified that my ex blamed his son's mother entirely, instead of trying to get to the root of the problem and the reason why he lies. It was horrible to go through, and I was worried sick at the thought of losing my children, when an 11 year old with no marks could make such crazy allegations involving my ex, his cancer stricken father and mother, as well as myself. I was so worried that if this could be so easy for him to do, that he could say anything, and I could risk losing my daughters. However, instead of getting him counseling, he just let it go, he has always been passive, and simply blamed the mother. To be honest, if I were her, I would have done the same thing. I never liked how my ex treated his son's mother, was always very short with her, and I always felt that he should have open communication, especially to avoid something like this in the future. 2 days after the CPS incident, I found out I was pregnant, and I decided to stick it out. My daughter spent 7 weeks in the NICU, total shock and was heart-wrenching. My ex went a total of 3 times. We both are far from perfect, but he is extremely lazy. We both work full time, however, I was always the one to take care of the children, he did not help out much. We did have many good times though. About 5 months ago, I just had enough. It was like he was a boarder in my home. He would come home from work and go straight to the bedroom to watch his Spanish soaps. It felt like the only help was financial. We needed a bigger home, and very soon to closing, we had another bad argument and he left. About a month later, he asked me back and said he was willing to go though counseling, anything, because he knew what he wanted and that he loved me and wanted his family. At the time, I had been talking to an old friend, and it felt good to have someone who was so helpful around, and communicative. I am not a liar, and never have been, so I told my ex no, and that out of respect for him, I was seeing someone, very casually, but I felt he should know. Now, I feel like that may be the biggest mistake of my life. In his eyes, another man is the absolute worse thing you can do to him....he can handle anything else but that. It took a couple months, but we ended back up on speaking terms...and he admitted to me that he cried and how hurt he was and that he loved me but was not in love with me, also he was seeing someone else, but that I would never be replaceable. I was hurt, I wondered who she was. He is in law enforcement and I helped him with every single paper to earn his BA. I figured she would be this beautiful, classy woman. She ended up being a trashy, unemployed 21 year old, with kids by a 55 year old man. As soon as I found out who he was seeing, he stopped all contact-he went a month without paying any support, answering my calls, or texts, nothing. I was in total shock. I had no choice but to take him to court. I know he is absolutely furious that he has to pay the amount he does. At the hearing for visitation, he actually brought the girl with him! She would not look at me, even though she had went to my friend's daughter's job to "relay" messages to me such as I would never get him back, and that sort of kiddie stuff. I could not believe he would condone this behavior. Even more upsetting, I recognized her. His brothers stepdaughters friend, she had been at the house one time. So, I wondered, how long had this been going on! So, to make a long story short, I am leaving a lot out. He doesn't communicate with me at all, apparently he is not allowed to. I believe she has her phone set up that when he gets an email from me, she immediately reads it and deletes it, he had his first visit Monday, I had emailed him twice and text him and asked if he needed me to supply diapers and provided the sizes. He never responded. He picks them up from daycare, as I DO work. He called me furious wanting to know their sizes, and I told him, I emailed you 2x and text you, are you not getting them? I would have gladly supplied them! This is so crazy! I get a text back, from her, I know how he speaks, saying its ok, I got their diapers. Drop off was wonderful. He pulled up with her in her car..and dropped them off in the doorway like packages. I just hate that he won't speak to me at all, the girls hve asthma and are on meds, I need to be able to have open communication with him. She apparently won't allow it. I have had a lot of time to think, and I wish we had went to counseling, my family fee