<human>: Could you distill the essence of the text into 1-3 sentences?

I am in a relationship with my SO [26m]. We met almost two years ago, and have been in a serious relationship since December 2011. We are raising our son together, a five-month-old wonderful boy. We have a great relationship, good communication, we're best friends, and we love each other deeply. We're a very happy family. My SO loves our son more than he loves me and would do anything for him.

However, we know that our son is not biologically my SO's. I dated my ex on and off since mid-2010. It was kind of a toxic relationship. He was eight years older than I was, and was verbally and emotionally hurtful. I stayed with him despite these things because I was young and stupid, and I didn't know how to get out without feeling guilty and placing all of the blame on myself.

I found out that I was pregnant in December 2011. I was completely shocked. I told my ex, and he asked me to get an abortion. I knew that I would not get an abortion. I also didn't want to raise the child with him because I didn't think he would be a very good father or partner... so we broke up. And almost a week later, I found out that he had killed himself.

I did not go to the memorial and I have not spoken to his family since before he died. 

My SO and I don't know how we should tell our son when he's older. We also aren't sure if we should tell his family. I don't know if I'm comfortable with it, but I also feel bad about feeling uncomfortable with it.

I guess I just want to know what others would do in my situation. How would you tell your child? Would you introduce the child to his/her biological family? I'm so confused and torn about everything.
<bot>: My son's biological father killed himself, and I don't know if I should tell his family, or how I should tell my son when he's older.