A friend of mine and his girlfriend have decided they want to live together. At present they each live alone in their own (paid for) houses in nearby towns. She has suggested that she moves in with him and lets out her own house and her rental income will mean she can work fewer hours and still contribute to the bills at his place.
I told him that this seemed rather unfair as she will be getting free accommodation while benefiting from the rent she receives from her own property. He will need to continue to work full time.
Surely whoever of the two moves out of their own property and lets it, should share the rental income equally with the one whose house they both live in. That seems more equitable to me.