"3 years ago I said let's try non monogamy"

And you thought that would end well because, why? All the cool kids are doing it? I know of not one instance where it didn't end in disaster.

Having some regrets over picking the alpha male bad boy, eh?

You might be right.

Sorry to read about your pain. Sounds like he's going to die long before you also. In his case that's a good thing.

I'm suspecting you had these doubts long before 20 years had passed.