So he earns a lot more than OP, and therefore has more spending money at his disposal?
OP moves in, rents her property and hands over the income from this for what should be joint bills, ie she pays most or all of the household bills, even though she has a lower wage, and therefore less personal money.
Does that sound fair?
I think the earnings are blurring the issue here.
Replace those incomes with more average wages.
Think of OP 's house as her savings, the rent is interest on her savings if you like, and is now accessible and part of her income. Puts her income up a little closer to his.
With her increased income, they could share the household bills fairly.
Then OP would have more of HER money in her pocket. Not as much as him, but closer.
So, current agreement they move in together. OP pays the bills from HER MONEY. (hopefully setting some aside for repairs and tax) Despite having less income than her partner.
Partner keeps all his money as personal money. OP keeps her remaining and much lower amount of money as personal money. Is that fair?
This looks more like a lodger agreement than a loving partnership.
Given a more equal amount of spending money, and split bills, I'd think his expenditure was his business. As his partner, if I were paying all the bills and as a consequence had much less personal money than him, I'd think I was subsidising him.
You earn 30k, he earns 70k. You pay all the bills. He can spend his money on whatever he likes. Really?