On almost all insurance plans, as long as the child is in school full time, they are still considered a dependent and would stay on the insurance plan, so nothing would change from the way insurance is handled now.
My parents bought me a car - an $800 Corolla Wagon - and I was responsible for the insurance. Plenty of kids didn’t have cars and got around just fine. There’s at least as many kids with cars as without, so there’s always a ride to be found. And my freshman year was in 2000, so times haven’t changed that drastically.
My parents gave me a $300/mo stipend for food and fun, and if I wanted more, I could get a part time job. So, I got a part time job. The money you’ll save by not feeding your teenager in your home will probably be around $200/mo, so you’re only looking at $100 more per month.
Cost of feeding him while on breaks? That is kind of splitting hairs. You wouldn’t bill your ex for the cost of the annual extended-family Christmas dinner that you continue to host post-divorce would you? IMO, once the kid is at college, visiting home is more of an at-will, when-affordable expense.
Travel to and from school: How far away is the kid going for school? They wouldn’t travel more often than on the major holidays and breaks, right? This seems like the only thing that would be really up for discussion, or even worth working out ahead of time.
If your ex-husband was planning for paying for college on a credit card before you divorced, to me, that says he was NEVER going to be financially responsible for college. Paying for four years of your kids life on credit cards is just about the perfect picture of financial IRresponsibility. And it doesn’t too much for teaching the kid about responsibility either. If anything, you’re saving yourself money with your ex not in the picture, because without a credit card, you’ll pay only the true cost for all expenses instead of an additional interest rate, and you and your child will be more likely to limit spending to neccessities, so there won’t be as many extraneous charges to pay off.