You have so much going on.
Try to fit in some time for self-care. You really need it! I know it's probably really tough to do that right now but even half an hour or 15 minutes a day of something relaxing or fun can help.
With so much going on perhaps filing for divorce can wait a bit. Not to say you shouldn't, not at all, but only if you can manage it right now. You don't need to pile more on your plate. Then again if it would bring you some peace, then the sooner the better.
I'm sorry it's come to this. If nothing else, detach, he has changed from the man you knew, detachment will help.