Some of these responses are bizarre.
I think it’s very sensible that women have financial independence from their other half. This doesn’t mean you don’t love each other, it’s just sensible planning. It is not planning a breakdown, it’s a worst case scenario. You’ve experienced when this has occurred without planning, so why put yourself through that again. Absoloutely sensible.
I don’t think you sound money grabbing at all. I also think he sounds very open to some sort of arrangement too and I’d also viewing it a pragmatic way. Kudos to you both.
My husband and I (when we got together years ago) had our house mortgage drawn up to state he out X amount in and me X and in the event of separation we would each take out initial stake and then split any profits 50/50 - this was to protect his inheritance he put in. This was my idea. As the years and new house went by we didn’t do that, and since had a child, relatively similar earnings etc. however if things went south we would financially be on equal footing. I never see this happening and been happily married for 10 years.
I would question whether rental is worthwhile - tax, issues selling and capital gains and getting a renter out should you need. I would be more inclined to consider selling and keeping a chunk back in a fund should you need to leave (put in an ISA so good returns but can also access it) and the remainder invest into the new house, so if you came to sell you’re also investing there and have ownership in the new properly so it is yours and not just his.
I wouldn’t be asking him for relocation funds, rental or a 6 month live in clause. You can manage this on your own. Pre-nups aren’t legally binding in the U.K. and if it were to get nasty he would have money to fight you in court - you wouldn’t, so don’t rely on this.
Maintain your independant from an employment perspective. This is just sensible from a risk perspective anyway. My DH met at work and now we chose to work at different companies to spread risk from redundancies etc if employers ever struggle or whatever.