How do you work out what's fair?
DP and I are thinking of moving in together, rather he is thinking of moving in with me (as I own my house, he is currently renting as still on mortgage to his XW house) I earn a good salary, can manage without his contribution but he feels (and I agree) he should pay something.
He currently pays £1k per month in rent, I pay £1700 mortgage. I think our food/utility bills are similar, save for he takes his DC out for meals and takeaways weekly, whereas that's more of a monthly treat for my DC.
I wasn't sure whether we should base it on earnings or income? He has his own business (only started up a couple of years ago, he's just taken on his first employees) which makes more than I earn, but he's ploughing lots into a pension and re-investing in the business, so his actual net income is about £1600, whereas mine is double that. However I can't afford a pension and I don't have my own business!
So how much do I ask for? Half? Less than half?