Zircon, please don't let yourself get all riled up in the unfairness of it all. That roads leads nowhere but to poor health and shame spirals.
You did the best you could with what you had to work with at the time. That is as good as it gets for anyone.
Your STBXAH is a very sick man. Try not to let his sickness infect you with overwhelming resentments and by all means, do not expect him to suddenly change into a thoughtful, reasonable human being.
Ultimately, whatever happens in court, you will walk away free of this toxicity. He will live in it indefinitely.