NTA, but I have to ask- why are you concerned about fucking up his relationship with his daughter when he already abandoned her? He’s coming back and demanding a relationship and custody when it’s convenient for him- how good of a father will he be to her? Is he going to pop in and out of her life when it’s convenient for him? If you allow this, she will have abandonment issues and learn that this is acceptable behavior from men. I say this from experience. My sons father left us when I was about 16 weeks and didn’t come back into his life until he was six months old. He petition for custody and got every other weekend. Now my son is seven, and hasn’t seen his father in a year. He hasn’t been to his house for a weekend in six years. He will occasionally ask me about him and when he gets to see him again and I never know what to tell him. Protect your child from being used as an accessory.