My STBXwife and I have a complicated history together. We were friends for years. Then we started something casual but the understanding was neither of us would have sex with anyone else and if we wanted to we would discuss it. When she got pregnant we entered into a more serious relationship and got married. I love our son and I do my best to be a good dad to him.

She and I had some difficulties over the years. We didn’t get married for the best reasons but we were mostly happy.

When I found out she was pregnant again I had some mixed emotions but ultimately came around. Then I learned she had cheated on me and the baby might not be mine. We did a DNA test while she was still pregnant and the child wasn’t mine and the bio father was a friend of hers.

I left our marriage and filed for divorce. When her youngest was born I went to court to establish officially that I was not the father.

STBX wanted me to raise her youngest child with our son. She was upset that our marriage ended over her having a child with someone else. She told me it wasn’t even the cheating that made me leave her but the baby and she said that wasn’t fair. That her child didn’t deserve to grow up without a dad because I care so much about DNA. Which is when she revealed that she had slept with someone else around the time she conceived our son and he might not be mine. That was a crushing blow for me. She accused me of wanting to dump him when I took a DNA test. My son is mine. But all the lies and the crap has made me hate her.

She still wants me to be involved in her younger child’s life and has been fighting against me only being our son’s dad. She tried to make the court keep me on her younger child’s birth certificate, but I was removed, she tried to insist that I needed shared custody of both kids or no custody of our son. The courts didn’t agree. They have us on 50-50 custody for our son. That’s temporary until the divorce is final. But this whole thing has been stressful as fuck. She’s doing everything she can to delay our divorce and she wants me to call the whole thing off.

I’m getting a lot of shit for denying her younger child. She has family members confronting me about it and I always tell them to get the father to step up or find someone in the family to be there for her younger kid.

I had a friend ask me why I won’t raise both kids. That I’d have stayed my son’s dad even if he wasn’t mine. I told them I would but I love my son and couldn’t hurt him by walking away after 7 years of being his dad or stop loving him like that. But I admitted it would have killed me to be a big enough man to help him know about his bio father and have a relationship if that was wanted in future years. I said I wasn’t selfless enough to want that but I’d have needed to and I said I wasn’t signing up for that knowing the truth ahead of time. My friend said it was a lame reason to not let the kids grow up as siblings kept together all the time. That family is more than blood and when the actual father doesn’t want to know it seems petty to let the child grow up without one. Some of that is what STBX’s family have said too. Other people are supporting me 100%.

I know I don’t want to do it and I would be resentful if I did try to raise her other child. But AITA for not being willing to?