I thought that our separation agreement was clear, and he paid tuition for our oldest two children to attend well-regarded Boston area colleges. Am I missing something?
As the cost of college has become such a huge cost, many parents are having difficulty paying for college. Given that you already have had two children go through college it makes me think that you have already dealt with a lot of the issues that people argue over such as choice of college, location and how the decision is made. Does he feel that he had input into the choices being made? Is he a part of the process? Has he suffered a financial setback? As college is a child related expense, it is usually modifiable in the event of a change in circumstance. He may feel that he has a reason to change your agreement. Mediation is a process that would allow the two of you to meet with a neutral third person to discuss these issues and to figure out an acceptable solution. Mediation is often used by parents when issues come up in the years after they have divorced. It would certainly be difficult for your son if his parents become embroiled in a serious conflict over his college education.