The other thing I'd add is that finding the Rear Admiral a saddle that she's very happy with is worth every hour and dollar that it takes. As well as investing some time with her handlebar position and setup- length of the stem, type and width of bars, bar-ends or not, tape/padding, etc etc. Basically set up her stoker compartment for maximum comfort. Stop for breaks, coffee/tea/lunch/soup/beer/wine, etc. And then communicate, relax and enjoy the ride and companionship, don't be too, uh, anal, about: cadence, speed, miles covered, keeping up with XXX, matching your time/speed on your single bike, etc. Like many other aspects of the man-and-wife life, oftentimes this is much more about relationship for her than it is for him; and much more about relationship for her than about other things (like miles, speed, exercise, heartrate, etc).

(Please don't jump on that too hard if it's not so for your wife/stoker, cuz I most certainly realize it's a generalization and not true for every couple, stoker, or woman. I'm throwing it in cuz it shows up often enuf, it might be, and hope it's helpful; move on + ignore it if it's not.)

And then, see Rule #1.

Here's wishing you many happy safe miles and years together.