Jack, first of all, I am so very sad to read your post.
You must be so unhappy and tormented with guilt. I know this because I've had to take this terrible decision. Not with my husband, but with both my parents. And I realise it must be a million times worse when it's your spouse. 65 years is a long time to share your life with someone else.
I'm trying not to cry as I type this, as your words have struck such a chord. There's no point in telling you not to feel guilty, because that's what you feel, and that's where you are at the moment. But if it's come to that point and you've had to take that decision, then it won't have been taken lightly. If your circumstances have got so difficult, then you have taken the right choice. And I'm sure you won't have made that choice lightly.
The loneliness must be terrible. For now, all I can say is that there are many people on Answerbank who had had to make similar choices, so there are many of us who understand. xx