I am a widow, and live in my own house with my two cats. I LOVE not having neighbors upstairs, downstairs, or on the other side of the wall. I think that's one reason for staying in my house.
I am also at the point where rent at an apartment would not be much less than my monthly mortgage, and there's always the hope that my house will appreciate in value so I can sell it to pay for that old folks' home someday.
But the biggest reason I stay here is that I lived here with my husband the last several years of his life. We had the house built, and put alot of our selves into the choices we made when building. I still feel like there's a lot of him here.