There is no woman so stupid that she would not see the arrangement as anything other than what it was: being a "kept" mistress, given a place to live, some money, and maybe a chance to be picked up by some rich old man to sweeten his last years in exchange for inheritance.
I agree. All a business arrangement of immorality IMHO. He has the house and money—she has a pretty face and a hot body. At the end of the day, they both got what they wanted.
There is a whole “dating” site for this sole purpose. Sugardaddy.com or something similar.