I feel for you, as I am in a similar situation. I finally got rid of my worthless ex a couple of years ago, who refused to do anything to help out around here...financially or otherwise. Was a nasty court battle, too, but well worth the temporary added stress to get that accomplished.
As far as houses go, mine is over 100 years old. About 7-8 leaks in the roof, that I know of (metal roof). No foundation...just a few strategically placed hand carved (squared) boulders. Floor joists are basically 'gone' in a couple of rooms. Original wiring with an old fashioned fuse box and inadequate plugs throughout for modern day usage so we have extension cords all over the place. Two unused chimneys because of severe safety issues. Windows about to fall out upstairs. The ones downstairs are mostly painted and nailed shut. Tried to loosen up a couple of them a few years ago and the frames started crumbling, so decided it was better to leave well enough alone. Warped and badly sagging floors that make the whole room vibrate when even my cat walks across the floor. An imaginary staircase that is no better than a ladder due to inadequate horizontal-to-height ratio, and the steps are all lopsided, unevenly spaced, and there's a broken step half-way to the upstairs that I haven't been able to access in almost 5 years (the upstairs, that is). No storage...not even one stinkin' closet in the entire place and no kitchen cabinets! Poor floor plan. Didn't even have a bathroom when we moved in almost 9 years ago. At least I have a shower and a toilet now. One of my older boys put that in for me as a Christmas present a few years ago.
Personally, I think fixing this place up (the right way) would cost way more than it would ever be worth. It was all hodge-podge put together through the decades by various previous owners, none of it appropriately lined up...just added onto as money allowed back in those days. There are crooked walls and crooked floors. And this past summer I discovered where a door once was on an exterior wall of the living room where they had DUCT TAPED a piece of cardboard over the hole and wall papered over it! I couldn't understand why the flooring had dropped from the wall there and I was seeing daylight between the two!
I'm sure there's more that I'm forgetting at the moment, but you get the idea.
And the truth is, I can't afford to do much more than what previous owners have done, as I am on a fixed low income (below poverty level). So I hang onto what I've got and pray that it doesn't collapse on top of us.
My only saving grace was the highway department paying off what I still had owing on the property because of some temporary easements while they put a new highway through in front of my place...plus they are taking a small tip off the far end of the field. But with the economy like it is, and the amount of work it would take to bring this old lady back up to code, I just don't see it happening. At least I don't have to make payments on it any more.
Meanwhile, I chose to get one of those barn-type sheds that has lofts inside. They have a rent-to-own place locally and the payments are affordable even on my budget. I am going to start fixing it up as a small starter home, and add onto it as I can afford to. Downsizing seems to be the new trend, anyway, and I would prefer living a simpler life at my age. Once it is fixed up enough to move into with my son, we will start tearing down this old house, salvaging as many materials as possible. Once the old house is down, we'll move that shed over to where the house is sitting and hook it up to existing water and electric. Then we'll start adding onto it, building it the way that I want it, utilizing as many of the materials salvaged from the old house as possible.
It will be a lot of work! But at least I can build it the way I want it over time.