So sad to learn of your situation. We lost my wife's mother last year to Alzheimer's. Her husband spent every day with her, walked over from his apt in independent living to have breakfast together, sit and watch tv, have lunch, sit and watch tv, have dinner, then back to his apt to sleep.
After she died he was bereft. He has no interest in continuing to live.
I strongly recommend you keep the boat and putter around on it a few hours a day. Stay in touch with the outside world. Your wife won't mind. If she were able to, I'll bet she would tell you to do it.
Good luck and God bless.