Thanks RR. back at you. So true , the sins of the father are visited upon the sons up to the third and fourth generations. Fortunately, it doesn't have to be that way if parents know enough to reach out and take advice by professionals, and others that have found their peace.
I think talking about the OP's childhood (noting that they were raised with co dependence) is REALLY IMPORTANT. In order to be able to pick good men to be in your son's life, you must reconcile the problems that existed in your life. I think it would benefit you greatly to talk to a therapist in order to gain what you may never have been taught, about finding successful people and relationships.
I hope the Poster comes back. This is such great post. There is nothing quite as impressive as a mother coming on this site to find ways of helping their children adjust and have less difficulty in their lives, as their parents.
I think your answer is good, especially from the angle of you decided to go on without him, rather than him abandoning you. I think that feels a little better to a child. Ironically, although you say you "don't want to inflict that on your son" (having a disinterested father) that is exactly what has happened. The Biblical quote of "the sins of the father are visited upon the sons up to the third and fourth generation" - meaning, father's inadequacy doesn't stop at one generation, it continues. The family pattern repeats. I don't know what kind of father your dad had, but your father has created two generations of fatherless children. I would work very hard to have other men in his life - if you have brothers, friends, etc.
You could talk to an Addiction's Therapist about having an Intervention for your Ex. Sure he has no other family to attend unfortunately (you could still ask them though),BUT YOU COULD BE YOUR SON'S VOICE AND SPEAK UP FOR HIM, TO LET HIM KNOW THAT HE NEEDS A DAD THAT IS SOBER AND INVOLVED. Your Ex was not given the tools to be a Dad, but that doesn't mean he couldn't change with the right prodding, from his SON.
Your son could become your Ex's True reason to find sobriety and a better, legitimate lifestyle that his son could be proud of.
If you can think only from your son's perspective.
And yes, likely there will be another more suitable father figure, but there would be nothing wrong with you seeing this from a point of compassion and at least try to save your son's biological father connection.
Maybe something to consider ?
I think you need to first communicate with your EX and see what he wants to do. When you told him to hire a Lawyer for custody rights that might have spooked him ( still no excuse to not be there for his kid) Does he pay Child Support? If you ever get married would you want your Husband to adopt him? You have lot's of options