Fiance wants to split all wedding and BTO costs 50/50 but earns twice what I do

You're not unreasonable at all, and honestly this conversation matters more than the flat. My husband and I split proportionally by income, roughly 60/40 in his favour when we started because he earned more, and we adjusted as our salaries changed. The principle we agreed on: we're building one household, not running two companies with a shared invoice. A rigid 50/50 that leaves one person unable to save isn't fairness, it's just optics. But the bigger flag is that he's not hearing you. Sit down with actual numbers, show him your take-home after the split versus his, and ask how you're meant to build an emergency fund. If he still insists on 50/50 knowing it cripples you, the money isn't the real problem, the mindset is.