First, best wishes to your wife on a speedy recovery.
Our home was built in 1850...then in 1925 they did an addition. My wife wants to do another addition at some point, but it is going to be a few years out.
You are correct that maintaining an old home does cost a lot. In fact, many people cannot afford it, which is why a lot of them fall into disrepair. I won't say how much I invested into our house--that was in great condition--over the past few years.
It is truly a labor of love. We will never move and I will buy up all the land around it when I can and it is available.
The downside may be the maintenance, but on the plus side, the saying 'they don't make them like they used to' is especially true. The boards under my sub-floor are hand hewn beams/logs that are almost 40' ft long in sections. My sub-roof is all hand hewn and varies in size, by the width of the logs.....even after 150+ years, the wood is solid and better than anything I could ever replace it with. All floors are hardwood and some rooms have woods that would now cost a fortune...all tongue in groove.
I figure a few thousand a year in maintenance no matter what. But you couldn't buy a place like ours and yours today if you wanted to. Now it's all plastic everything and particle board.