You wouldn't be throwing your money away any more in an apt/townhouse than you would be in their house! Rent is rent! They just don't want to find something else to do with the house after they move...they want you guys to take care
of it for them (and pay rent). And every time you change one little thing, they are going to be complaining about it. And seriously, can't they just wash the sheets? If they rent the house to you, you really don't have to even let
them stay there, because it isn't "theirs" anymore. And six hours isn't very long if you know you have somewhere to stay (for free and for as long as you want!) when you get there.
Sorry you are having so much pain. It could be endo, but it might not be. And yes, endo can cause you to not be able to have children, but those are only the most severe cases. I have endo, and I got pregnant after trying 4
months. So it isn't a childless sentence for most people that have it. (Around 80% of women with endo get pregnant, compared to 90% in general.)