I've been thinking about you the last several months, wondering how you were doing.
I'm so sorry you find yourself here. When you said earlier in the year that you were giving it another go, I crossed my fingers, but at that point, you hadn't written anything that presented him as a good candidate for R.
One thing seems consistent to me - that he has difficulty sitting in his own crap. And shame. And emotions. I'm really sorry that he is such a coward.
He has really put you through the ringer this past year - right on the heels of having a new baby at home. That's a big big mountain to climb back up from the gutter and you know - he just may not have it in him. And I don't mean just to make the marriage work, but to own the pain he has caused you and your baby.
I know how that feels. A ton of us here in this forum who have been divorced know how that feels. And it really stinks to not have our hurt and questions ever acknowledged.
But his parents are right on the front that you should quit talking to him (but not for the reasons they think - I suspect they just want the noise and conflict to stop because they can't handle it either). You should quit because you're just beating your head against the wall with someone who is acting like a piece of shit. He is not (at least at this point) able to be decent. And that leaves you hurting and confused. And I know you don't want to hear this, but he may never be able to be decent and address everything he did.
Time to move into self protection mode.
You can be a fabulous co-parent by being polite and honest but at the same time putting up the biggest boundary and wall anyone has ever seen. Let him run around chasing his own tail or emotions or whatever it is he's doing.
Be frosty - don't let him into your head and emotions any longer. He doesn't deserve them. Reserve those for people who are kind human beings.
So - to ask the question I always seem to ask you - what are you doing for yourself? What kind of armor are you putting on to protect you and your son? Have you consulted an attorney? Are you getting your own therapist? Are you asking for help in caring the baby still so you have some hours to yourself? Is he back in his apartment? If not, when is he going?
I know how awful this is - hope you will keep posting and find a way to get all that ickiness out of your body.