Basic question: Should my considerably better paid ex-H contribute to DS's special education above and beyond maintenance.
Background:
ex-H left me & two DCs 9 years ago when they were 1 & 3.5). Divorce was granted 7 years ago, after court battle to get him to cough up. In the intervening years, DS has been diagnosed with ASD & then multiple cognitive impairments, which mean he has learning difficulties.
I have moved heaven & earth (literally in that I moved house to a cheaper area) to free up some money to send DS to a school that specialises in teaching boys with learning difficulties & ASD. I also work full-time & am very frugal - just so you don't think I am a money grabbing witch! 
I think ex-H should contribute to this, but he refuses. Do I have a hope in hell of getting him to contribute, or do I just accept that if I want DS to go to a special school, I have to make all the sacrifices?