Oldest child's Father

Bianca • 28
I have 2 children by 2 different men,and sometimes that really sounds bad to me but anywho. I meant my 8 yr olds father back in 2005 I was 19 he was 37. At the time he told me he was separated and getting a divorce and of course I believed everything he said. We so called dated for a while and I ended up pregnant in 2006 with my 1st child ever. I told him and To my surprise he was not happy and at that time it confused me. I told him I do not believe in abortion so i was keeping it And he said OK I understand. I thought it was fine until one night I got a call from his WIFE! She explained to me that they are very much married and still living together which I knew that but he had told me that we would get our own place me him and the baby. Well he ended up back with his wife but the next year was back with me and the baby. 5 1/2 years of torture with being with him went by which I understand that could have been my Karma. He finally left me to marry someone else, and when that happened he also stopped taking care of my 8 yr old. He has not seen or spoke to her in almost 5 yrs. I have done some of it due to him constantly telling her he was going to see her soon and would never come and then they would talk on the phone and he would say I'll call u later and would never call back so I did what I felt was necessary to protect her heart. Now the guy I am currently with we have a 9 Mon old and he has been there for both of them every step of the way he taught the oldest how to ride a bike, tie her shoes buys her what she needs and wants does things with her he is amazing with the kids, but now the oldest one father wants a relationship with her and I don't think it will work he is trying to come and go as he pleases and I told him u can't do that with children. What should I do should I let him or keep her protected at all cost?