If you are indeed contributing to 50% of the cost of running a home, and doing most of the cooking and cleaning, your lady friend does not value your relationship to be above her altruistic tendencies. You have a big decision to consider. Once you start using your equity to "pay her rent" is she liable to ever agree on a suitable joint ownership property? Why would she? You may be better quietly finding somewhere that you alone can afford to rent or buy, and when your pieces are positioned, say I think it is for the best. Can she afford to maintain her current property unaided? It is almost a truism that 2 can live as cheaply as 1 ,but only when any burden is equal.