Pre-nup ????

FBaby

That wasn't an average case because of the wealth of the couple concerned.

Not just that but the key factor was that they had married in Germany, not the UK.

The Appeal Court had agreed that Ms Radmacher, thought to be worth £100m, should be protected by the terms of the German marriage contract. Mr Granatino was fighting to get that ruling overturned...She said: "For Nicolas and I, in our homelands - France and Germany - these agreements are entirely normal and routine

So really irrelevant to the OP!

elsien

I'd also suggest having a conversation with him about it. Maybe not starting with "I want a pre-nup" but more what you've said on here - that you're committed to him but you do have some concerns about the what if's, so what would he think was a fair way to go about things?
Then instead of presenting him with a fait accompli which he may regard as a not entirely fair ultimatum at short notice, he can be part of the conversation. After all, if your marriage survives another 15 years then you split up, he's got 25 years worth of paying towards bills, maintenance, etc but would potentially walk away homeless with nothing at the end of it. In his position, how would you feel about that?
I'm not saying don't do the prenup, but I think you need to consider both parties thoughts and maybe go along the lines of percentages, or invalid after x no of years, or whatever you both agree on.