@jennifer1861,
If it leads to a breakup (or a break, but not intended to be a permanent one), that could be what he really needs. Consider if he were an alcoholic. You can keep driving him home from bars, or you can take his keys and make him walk.
I'm not sure what the comparable metaphor is in this case. Maybe consider a food budget? You're saving for XYZ (a trip, a house, a car, a gift for someone having a special birthday, I dunno, make something up) and so you're on a budget now. To do that and make it convincing, you'll need to show you're on a budget for everything else. I don't advocate lying, not really, but this is a potentially fatal disorder.
Sigh. I know you want to be supportive, but your support is making it easy and comfortable for him to commit suicide by reverse peristalsis.