NLW- I think we were posting at the same time. I just read your update.
Perhaps now is the time to consult an attorney. If H is reluctant to share financials with you then you may have to hire someone else to take up this fight. Is there a way to get H to continue paying fees until a permanent settlement is worked out? Not sure of the laws where you live but in the US most judges would consider his withdrawal of support unacceptable unless he can show evidence his income dropped substantially. At this point your primary obligation is to your son and if you have legal recourse to get him through school then I would pursue that ASAP. In our country you can get an emergency hearing so a judge can rule to keep everything status quo.
My H has also completely taken us off his radar. It is as if we no longer exist except as distant relatives he used to spend time with. My children are hurt but the stronger I am in carrying on the stronger they seem to be. If your son sees you fighting for his right to graduate from the school he knows and loves then he will model that strength no matter what the outcome.
Another handy tool is to communicate via email but whenever possible cc someone else. For instance if you are discussing school arrangements then call the headmaster to get information, relay information to H in an email and copy the headmaster. H can't manipulate or rewrite facts if there is a third party in the conversation. This is also why a lawyer is helpful if H is withdrawing support.
I wish we didn't have to be here discussing these things. I trusted H 100% but now he is so erratic that I am relieved I hired an attorney and can at least get the finances ironed out. i keep telling myself that if these decisions are made as if I am handling a business and not being vindictive then I am on the right path. The emotional side of things will have to wait.
My D16 loves her school and I know having to switch would be completely unfair and cruel at this point.
M:25 years at BD w/ 2 daughters BD: 5/14 Separated 6/14 - H moved cross country w/OW D Final 9/17
“I can be changed by what happens to me. But I refuse to be reduced by it.” ― Maya Angelou