Blended Family drama...what Can I Do

Well, there are two legal demands that you have every right to make:

1. You can take him to court for child support. If you're like 95% of moms, you'll win, and he'll have to pay your court fees. You may have an ongoing series of legal headaches making sure the court order is enforced, but ultimately you can secure these funds for your son.

2. Or, you can request that he give up his legal claim to paternity and let your husband adopt your son. That might be more satisfying emotionally, but you'd be forfeiting the funds.

What you CAN'T do? Make a positive relationship happen if your ex doesn't want it. Sorry, there's no way to force that. And why would you want to? The guy sounds like a jerk and a terrible role model. My advice is that you move past that idea and pursue either option 1 or option 2.

Mira's right. You can't force him to be a dad. You get Child Support Enforcement to chase him down and pay for his kid or you can ask for him to let your husband adopt the child. If you go see the child's grandmother, let it be because the child has a good relationship with her and not because you expect to see your ex. I'm assuming that at this point you have sole custody and no every other weekend order for biofather? If not, then his visitation is at your discretion. If he has no intention of being a father, then maybe he can be a paycheck. It's not like you haven't tried.

He's not even contacting his family so that says he's not really interested in family in general.

Hopefully your husband is a good role model instead and you can focus on his relationship with your son vs the ex who doesn't really want to be a part of it.

I think what you're doing, keeping in touch with his mom, letting him know he can see his son, is great.
How long has this been going on? How old is your son?

One thing that wasn't clear to me: I think that you should send him a message stating very clearly that you will NOT let his non-payment stand in the way of his seeing his son...that his son needs his father's presence more than his money and that that is a separate issue. It sounds pretty elementary and maybe should be able to go without saying, but lots of fathers feel ashamed and less worthy of seeing their kids when they don't pay support, for whatever reason. They anticipate having to deal with a cranky ex and, simply, opt out. There's no excuse for it, but I think that it might be a valuable move on your part to go ahead and say that to him...no judgment. You know how you can lend somebody money and then they get scarce when they can't pay you back? They don't want to look into your eyes knowing that they owe you, imagining that you are assigning all kinds of judgment to them. Do what you can to release him of that concern, and be sincere.

You can still pursue child support, but keep it separate. Also, if you are getting by okay without his financial input, you might consider not actively pursuing right now, until you see if easing up on that part will draw him and make him want to be more involved. You can revisit it later. It just depends on what you think is more important for your son right now. There's a scripture that tells us that where you find a man's treasure is where you'll find his heart. I think that a lot of women subscribe to that and turn financial support into the biggest issue, which is such a turn-off for the men that they're able to use it to help explain why they fall off. Clearing some space for your son to have his father might be worth taking this off the table for a while.