The judge will look at his income and his bills to determine his ability to pay. The judge will look at the dependent spouse’s income and bills. There is case law which states that a supporting spouse cannot be forced to pay alimony that will exceed his ability to pay. (e.g. If he makes $5000/mth, his current & reasonable expenses are $4000/mth, and the child support is $800/mth, alimony will not exceed $200.) Adultery is immaterial and will not change this, except that if he did commit adultery and can afford to pay it, some form of alimony payment will be mandated barring other evidence.
As far as the standard of living prior to divorce and college goes, you must remember that it costs more money to run two separate households than to run one. A family with two working spouses living under the same roof has more discretionary income than two single parents living in separate residences each incurring their own set of bills, especially with the tax structure set up to give more support to marrieds.
Circumstances change and while plans may have been made to completely support the children through college prior to divorce, that cannot be guaranteed after. Your world has changed, and now the situation is completely different. If the couple were still together and the husband had become disabled, you would not be able to afford college for the kids either.
It’s honorable to pay your kids way through college if you can, but if you can’t, one must remember that while college has become a necessity to get better paying jobs, children are quite capable of working a job themselves to supplement loans/grants and their living expenses. (I know, I worked and paid my way through an advanced degree myself with absolutely no help from either parent, not even food money. It wasn’t easy, but then again I learned more than from just books by doing it that way.) As far as receiving credit for supporting a child through college goes…if you can afford it, I believe that you may be able to write at least some of it off on your taxes. Check with an accountant, and they may be able to help you further.