I am familiar with this scenario as I work for a similar set up, in the end the wife put her foot down, and refused to have anything to do with it, the business moved out of the home and employed a replacement for her. (It still makes a good profit). Also before I retired I worked voluntarily at a job where I was tied to being in for deliveries etc, and had to stay in during the lunch break, and took no holidays, except for two weeks when we closed. It takes its toll and there comes a point when it is not worth it.
Can you reach a compromise and retire in say 2 years time? Will the business be sold when it closes or be wound up? Most accountants/book keepers are trustworthy, and with your overseeing it, you should be able to find someone to help out, so that once they are trained you could take a break. None of us know what is round the corner, if your heart and body are saying enough, listen to it.