Step Parent Adoption / Terminating Parental Rights

My ex and I had our daughter (7) when we were engaged. Long story short, he raped my little sister 3 months before our wedding and i obviously called it off. I felt I had no other choice after a ton of research and allowed him to continue to be in my daughter’s life. She was almost 2 when I moved out of our home. He claimed he understood that he should never see her again and that I could have all rights to her. I didn’t feel that was fair to my daughter and we came up with a plan. He saw her on Wednesdays and every other weekend. This was not court ordered, it is the schedule we just agreed on. He met someone before I ever moved out and she moved in right as I moved out. They got married and are now divorced. His now ex wife says he’s extremely abusive mentally, verbally, emotionally and physically. Which, I can confirm is true. I received a call from his wife 1.5 half years ago stating that he had hired a hitman on me. We were knee deep into a custody battle. I was scared for my life. He found out that I knew and I’m not sure what all happened on their end after that. We did file a police report. They couldn’t do anything because she went through his phone and found the messages. She did not screenshot in fear for her own life. He lost his court case and I have full custody of our daughter. He hasn’t seen her in 1.5 years. He hasn’t talked to her in 1.5 years. She is terrified of him. My now fiancé, has been in her life since she was 3. We now have a son together who is 7 months old. And although she very much remembers her biological father, my fiancé is her dad. She calls her biological father by his name by choice. We did have a guardian ad litem come to our home 1.5 years ago and had a great experience. Her biological father failed to ever allow him to come to his home.

My fiancé and I are getting married in a few months & my daughter wants his last name too. We would like for him to adopt her. There has only been one time since her biological father has asked to see her and that was on her last birthday. He freaked out and blew up my phone and after that he hasn’t contacted me since. That was 4 months ago.

He is so dangerous beyond belief. I want to protect my daughter in case anything happens to me. Naturally or caused by him. I have no proof of the hitman situation other than it was his wife who called to warn me. I need to find a way to terminate his rights, but have a huge fear the court will fail us and somehow give him more rights and visitation. I’m terrified he’ll kidnap my daughter or even worse, hurt her to hurt me.

Some info to add : - i am located in Ohio - Her biological father does know we want to do this, but Im not sure if he’d agree - he does not pay child support - I do allow her to see his parents— her grandparents and they understand that she is not to see him or talk to him - his own sister said he is the biggest narcissist she knows

Thanks for reading this far. I need any help/insight I can get. I understand we need to be married before he can adopt. I’m just trying to be as prepared as possible with as much information I can get. And maybe someone who relates to my situation a little bit.