How do I manage finances with DP moving in?

[EvelynSalt]

Hoping to get advice from those with more experience than me in merging households. DP and I each own our own house. We have decided to get engaged / married soon and, in parallel, he's planning to rent his house out and move into mine (I'm fine with this, his house is quite a bit more cramped!). The plan then is to sell mine and buy somewhere together (he can manage a deposit contribution without selling).

When he moves into my place, what should be the arrangement? Should he contribute 50% of my mortgage and bills? Or does this expose me to risk if we ended up separating? Are there any legal docs that should be drawn up for unmarried couples cohabiting to formalise the arrangement? He will be better off as his mortgage should be partially covered with rental income and I want things to be fair. At the same time, I don't want to give up my financial independence.

Conscious that I may well be overthinking this but I'm an avid planner (owning my house outright saved me when I managed to get my abusive ex out, so I think I'm a bit hesitant to give up any independence in terms of finances).

Any advice appreciated!

Don't let him pay the mortgage at all. I'd speak to a solicitor to ensure you do the right thing, but the most simple thing is not to get married. Marriage really changes things and gives both people more rights depending on the length of the marriage. Personally I would ask him to transfer a set amount into your bank account and pay the bills yourself from that account. Keep everything in your name

You need to decide if you see marriage as a joint enterprise in all senses. If so make sure you put all assets in both names including his flat. Talk openly about pensions savings etc. I am always mystified by people who get married and still see their finances as two individuals. Don’t get married if you don’t want to share as pp said. Living together and being married have completely different rights to each others finances.

Sorry, I should have been clearer. I meant for the portion of time where he's living in my house but we aren't yet married (assuming we will be engaged for a bit before getting the marriage organised - although as we're not fussed about a big wedding perhaps not too long).

I'd suggest you both put a percentage of your pay into a joint account & pay all the bills out of that. Keep the mortgage payments coming out if your own account, in your name - just set up a regular transfer from the joint account to cover it. I know it feels like juggling, but you can see what you're both contributing & where it's going.

It was a LONG time ago, but when I bought my house & my then BF moved in, my solicitor drew up an agreement that he would have no claim on the house.

Joint account for bills, gas electric council tax water ( don’t forget you will lose your single person council tax reduction), and food.
Each contributes either half of this or a % if your incomes are hugely different.

Keep your mortgage and house insurance from your account., so it can be clearly seen he is not contributing to this.

Really consider if marriage is right for you, as you seem to be very well established financially and marriage is a business transaction to favour the less well off person