Hi UA,
I remember your story, too and have name changed (I keep the TMSB frame: TooManyStuffedBears, TeachMySelfBalance...)
I am glad you are doing so much better. You really had a hard hard time.
Please don't feel guilty about benefiting from what that turd left behind. It is yours now and not associated with him any more.
It will be hard when your dear little boy talks about his father. I know you never want to hear about him again, but the little one will need to voice his feelings about it to let his brain process it, iyswim. Create a few stock answers and keep to those for your own stability. Try not to be too negative as this may influence the little one in creating his identity: dad was bad, so that is why I am, etc. Stepping away from the negativity isn't defending him (IMPOSSIBLE!), it is more to preserve your own hard fought tranquility.
I don't do well with my past. When the nasty emotional gremlins pop into my head I have to remember that and consciously shift to living in the present.
Also, please, you do deserve peace of mind. It may be a habit to have crap circumstances plaguing you-are you subconsciously looking for, justifying it? Just guessing, but if you do/are in counselling, it might be something to look in to. You are worth a peaceful life, UA. You do deserve it.
Have a wonderful Christmas!