Right, I've pondered & this is what I think is fair for you both.
as I said earlier his place gets rented out and any profit is put into a joint savings account towards a future joint deposit if you separate in the meantime it's split 50-50
He pays 5050 on council tax, electricity, gas, TV license, water rates, et cetera, et cetera
You pay for anything that maintains the property, including things like Boiler Service Is et cetera
Obviously, you continue paying for the children's activities uniforms shoes, clothes, all the usual
You keep on doing as you do now read meals out and stuff like that
He organises and pays for a weekly cleaner
Supermarket shopping, et cetera 50-50, yes it's also feeding your children but he's saving a lot on only paying half of the utilities he was paying living alone.
Even though he's paying for the cleaner, he still needs to act like he lives there cleans up after himself and Max in with the other things the Cleaner doesn't do like putting bins out emptying the dishwasher generally tidying up mowing the lawn
Have you talked about his role in the children's llives, when he moves in? I think that can be a very tricky thing to get right and obviously it's different depending on how old they are,