The after math

So my relationship with Kylynn's dad stayed in tack until after I was let out on the bracelet. I looked at things in a new light when I looked into my daughter's eyes. I wanted so bad for my little family to stay together but there was nothing that I felt would change. Her dad has been doing the same pattern in his life for so long that I didnt believe that he would ever change. So when he got a 3 way to me one night I told him I was done. Not only because I needed to be me and find myself again but I had heard some pretty desturbing things about stuff he had done that I didnt know about until now.
I told him I wanted him to sign off his rights because in my eyes he didnt deserve to have rights to Kylynn. But I decided to be the bigger person and give him a chance to prove that he has changed and will be a different person when he gets out of jail. So we were friends and we would talk via letters about Kylynn and how she is doing and things like that. The what ifs and such. Then he called me one day and was talking about how he couldnt wait to try again and start over fresh with our relationship. I felt my heart drop how was I going to tell him that there was no more us there would never again be an us because i didnt trust him I didnt love him anymore. So I told him the truth and I knew he was going to lash out at me and he did just that.
He told me I never loved him because you dont loose love for someone over night. I told him I had lost love along time ago. And he said he didnt want to talk anymore and that I didnt have to worry about him. But to know that I would see him in court when he got out to fight for 50/50 custody of Kylynn. I said its not gonna happen and my heart was saying what if it does. I would crumble if he ever got half the time with Kylynn and i only got half the time. I love her and I raised her for her whole life. So my question to myself was how the helk does he think he deserves to have her when he hasnt really been there for her in the last 18 months? He the hell does he get off saying hes gonna take me to court!! I mean he has yet to pay ANY child support from any of the time he wasnt around and he has the adasity to say he wants 50/50 custody! OVER MY DEAD BODY!!!! So now the question that goes through my head is do I get his parental rights taken from him for not seeing her or do I let him try and be a dad when he gets out of jail...