Interesting quandry you pose here, my dear. A couple of questions/possibilities come to mind while I read:
1) If he is really hell-bent on the Baja property, would it be possible for him (or you for that matter) to just have him go ahead and finance it in his name only and have him be responsible for the payments out of his own pocket?
2) Have you ever thought about giving up the role of being the family accountant and turning it over to him? Just saying, "I quit. You do it." Sometimes that needs to happen so the less financially responsible party can really see what comes in and what goes out each month. (Another possibility would be to hire a real accountant to manage your family finances [sounds like you could] and let the professional be the bad guy -- removes you from the "mommy" role.)
3) I don't recall what your previous line of work was. Perhaps if you could share some of that, we here could help with a little brain-storming session for some work-from-home options.
