He’s very tight with money. He’d say frugal but …
Ah, this is it. Tight people are tight with everything else. It is a sort of mental illness - constantly calculating the worth to themselves of everything. Always keeping tabs, always checking the balance on that internal ledger, always constantly calculating whether they have made a profit, got the better side of the deal. It isn't just money that misers hold on to. I bet you already know this, but you have been busy blinding yourself by writing it off as a quirk 'cos his poor, sad, deprived childhood or something.
When you have a spreadsheet constantly open inside you where your heart should be, it is an easy equation. There is no value to him in giving you what would make you happy.
On his side of the equation he has everything he needs, sex, child, comfortable house, disposable income, whatever else. On the other side of the equation, your side, is 'it would make her happy'. When someone is tight, that side has no real impact on the equation.
PLUS, lets be honest, he is also deeply stupid, because he hasn't actually calculated properly and he will be worse off financially when you leave. Miserliness is IMO the most off-putting characteristic a partner can have, and stupidity is a close second...
So, you can force the issue. You leaving him would do this. I can PROMISE he will suddenly be booking a wedding because he will all of a sudden, understand he has severely miscalculated those two sides of his ledger. He has made a serious error in his spreadsheet.
Unfortunately by then you will have seen inside him. Who wants to be having to force the person that should love them and want to do it, down the aisle?