FWIW - my ex insisted on having something in the divorce decree that committed us both to a fixed share of undergrad college costs for our three. The lawyers actually kind of discouraged it, but he insisted (I didn't have a problem with it). I'm sure my ex wanted to be protected against me flaking out on my share.
But now, I'm glad he put it in there, because he's being SO cheap with our kids who are not currently in college. I can only imagine how hard it would have been to get him to pony up his share of college if it wasn't in writing.
