What would a fair property split be?

[Rainbowhairdontcare]

If I put in all of the house deposit (15% LTV) and pay 2/3s of all bills, would 60/40 tenancy in common split seem fair? We'll eventually marry so to some extent it's pointless but I'd rather protect myself in the meantime.

60/40 would be extremely generous to your dp - 72/28 would be closer to each of your financial inputs i.e. 15% + (2/3 of 85%)

Ty! I was trying to do those maths in my head but couldn't figure out how. I know he'll accept the 60/40 but unsure about the lower proportion (he mentioned than in more "normal" gender roles people would see such a split as unfair).

Gender roles are completely irrelevant, it is simply maths. Of course he will accept the 60/40 he is getting 12% of the house for free, bringing nothing but gender roles into makes him sounds manipulative!

Why is he contributing absolutely nothing to the deposit and so little to the ongoing bills? How does he justify a significantly bigger proportion than he is entitled too without contributing financially? This may be the first red flag in your relationship.

You need a deed of trust protecting the capital sum of the deposit, then split the remainder but I wouldn't be doing 50/50 with the remainder because the majority of the risk is with you.

I agree. Protect your deposit and then do a 60/40 split of equity.