I think he is going to leave in January, so I really must file. I cannot trust him to do the right thing regarding money. And it has cost me thousands and thousands not filing before this. I really have ruined my financial future by waiting.
I know exactly how you feel. It's a horrible situation. I faced a similar situation and chose financial ruin over divorce. Not recommending it to anyone, though. There really are no great options. It's terrible to be put into that place where you have to make that decision.
Be true to yourself, be the best BM you can. Think long term and do things you will be proud of, later in life.