No, you're not crazy, but as someone suggested, be sure you can both fit comfortably on the GTV before you do a deal. I tried putting my wife on a GTS 300 and the wide rear compartment made it very unpleasant for the passenger.
If I might make a suggestion, sit on the GTV then go sit on a Piaggio BV350. Granted, no classic styling, but does have some features like larger wheel and more HP that could make it better for you and your wife.
As far as getting rid of your motorcycle for a scooter I fully get your dilemma- I've got an R1200GS that mostly just sits on a Battery Tender while I tend to jump on my old Vespa for most of the normal stuff that I do. I haven't sold it, but it's because I'm having to come to grips with the realization that I'll probably never have another uber expensive awesome bike again.
I should get a small modern twist and go, and it would cover most of my needs. Maybe next year will be time to say goodbye to the beemer. Good luck with your decision!
1980 Vespa P200E