Hi and welcome to the forum. First, if you are using your real name, you may want to change it to something else as many do here so you can be more anonymous.
We're glad you're here and most of us have been right where you are right now with our DCs. We started out paying for our Difficult Child's college but after he abused that privilege we stopped. He took out one loan for one semester and defaulted on that loan and now is making arrangements to start paying it back.
It has been our experience that when they're on their own, they can get loans. He got more than $3000 for one semester.
I would make sure, as others have suggested, that you are very clear on what the divorce requires, and then I would make sure that much of the responsibility for college rests with your stepson. That will build his character, sooner rather than later, if he has skin in the game. We often say here: stop the flow of money. I found out the long hard way how fundamental that became. Once I finally stopped paying for things, then he had to face the consequences of his own choices and over time (a long time) he finally started taking responsibility for himself.
Your stepson may carrying on like some young people do, and it will pass. Or, it may be a deeper problem. Time will tell.
All you can do is to decide with your husband what you will and will not do. What is reasonable. What makes sense to you. Offer to help...but very slowly and carefully. If he doesn't appreciate it, pull back.
A person---any person---who wants to go to college bad enough will find a way. Looking back, it's good to be a little hungry for things, for things not to come too easily.
Your stepson behaved badly and it appears, from what you wrote, that he's flaunting it. I know that kids of divorce play one against the other. My Difficult Child did that with his dad and I. I found that if I would say less, but make those words count, I could command more attention.
Most of us teach our kids how to treat us through years of not being firm enough. I know I did. I spent way too much time talking, reasoning, trying to make sure we "connected." Now, I try not to act when I'm angry. I try to decide what is reasonable. I think about what I want and what works for me, as much as what works for him. I try to keep it simple. Sometimes I even write it down to get really clear. Then, I try hard to be consistent and not be distracted or shaken from my script. Sometimes new information occurs and I always can change my mind.
I know this stuff is hard. Having your house trashed out is not fun and I'm sure you feel disrespected right now. I would too. Hang in there. We're glad you're here.