I kind of had a feeing you wouldn't leave him OP. Powerful aphrodisiac, someone adoring you, being good in bed.
Declarations such as 'I wouldn't take a penny' are meaningless as he doesn't have a decent pension, or a house, or assets, or savings all of which you have, so every time you go out and he spends money on you, he's accruing more debt.
If you can honestly leave him to live in his rental, and only pay what he can afford (very little, not holidays, not dinners out) and still have a relationship, great, but that wouldn't be what you want in terms of lifestyle.
All other options are basically giving your hard-earned money and security to him to the detriment of your children (marriage, him moving in).
Maintain separate households and see how he is with money. I know the answer, I think even you know the answer, but its intoxicating and you seem to want to learn the hard way. I watched my mum take in someone with no pension and no assets at the same age into our family home and it ended in tears, but nothing would have prevented her, so that's what happened.