You can sift through this thread and get as many different stories as you want. And there may be some good points and make you think about different things, but when it comes down to it, it's all about you and your significant other and your values/personalities. There are tons of couples who have incredibly strong and solid relationships and are truly happy. The travel benefits are obviously a huge benefit for the two of you to get away, assuming you are both cut out for the risky essence of standby travel. But on the flip side, there are many people who can't handle it. It really all just depends on the couple. I'd venture to say that deep down inside, you probably know if you're cut out for it. But in case you really aren't sure, a few questions to ask yourself: is your wife independent, is your wife controlling, is your wife jealous, is your wife trustworthy, does she trust you? Now ask yourself those same questions about yourself. If you answer any of those questions unfavorably, that should be a big ol' red flag.
Bottom line, there are pros and cons to the job and how it affects the relationship. The old adage "Absence makes the heart grow fonder" is very applicable to relationships. It keeps things fresh. And being able to hop on a flight and go to some cool places for a couple of days is really awesome. But the stress of being apart, things going wrong when you're not there, etc. can be a lot to handle.