I’ve been on both sides of this equation. There is no simple answer but if you’re the one with the money, I suggest you get used to giving with an open hand or it’s never gonna work. I was a big fan of the "ratio method", unfortunately it always seems to end up incentivizing the person paying the smaller ratio to work less and less. Now I’m a fan of the "live your life method". Just get used to paying and stop worrying about how he’s wasting his/your money. You’ll both be happier in the end. If you can’t do that with him, then he’s not the man for you. Keep looking.
Strangely enough, when I learned to let go of the reins and just enjoy the ride, the other person seemed to spend less and depend on me less as opposed to when I tried to control everything. As always YMMV, but happiness has a cost. Get used to paying for it.