Besides, three touring bikes just don't make any sense.
Brian is completely correct there Bill. Truer words never spoken. 2.6something is ok. But three is just nuts.
Is the Ultra the keeper because it's the over the road bike or is it the over the road bike because it matches the trailer? If the latter you might find yourself buying some paint later when you find that the Road Glide is tough not to ride for a distance bike when you have the option.
If the SG and the Deuce are chose between as local hoppers do the saddlebags make a difference on the Street Glide? If so that's a decision maker. If that's not it they're both cool bikes and the old Deuce is cheaper to maintain and insure.
So what's a guy to do? Perhaps..... Perhaps you should heed your wife's profound advice but only long enough to fully evaluate the options. Such an evaluation will of course require riding each bike long enough to really fill in the data necessary to complete a full analysis. You'll be working toward the responsible and frugal decision of selling one. But it might take a couple years of research to reach the correct decision.
Just sayin'.....