Hi, I am military. Your son needs to check what he qualifies for educationally. Is he Reserves? Does he go to a state or private school?
Your son has the GI Bill, the Tuition Assistance, and the AD waiver (depending on the state he is in, his veteran status, and what type of school he goes to). All of these combined will pay for his semester and then some. Along with the GI Bill, he should be getting some sort of BAH. The new GI Bills give more money than the old.
Don't let your son's college situation be the reason you won't file for divorce yourself. Your son is a big boy, he can figure out how to pay for college himself (like the rest of us). If for some reason, the Army entitlements aren't enough, then there are student loans your son could get.
Do you really want a divorce? Because your son's education shouldn't be the reason for the hold up. Especially when there is so much money out here for vets to go to school, along with scholarships and loans. In my state, veterans go to state universities for free, including any state law schools.