Oneday: It's worth bearing in mind that once you've got the seniority to move to a window seat with QF (yes, yes, I know...) you've actually got a bit of choice as to how you run your life. As a 737 F/O you can get fairly few overnights and never actually be away for very long at a time; average trip length on the 767 and 330 is around 4 days versus maybe 8 or so on the 744. Some people find the longer trips (and longer breaks in between) on the 744 are great for their lifestyle; others (me included) would forego the big pay rise on the 744 to avoid being away for big stretches at a time. I guess what I'm trying to say is that there's no one simple answer.
Also, living near your wife's family (however unattractive this might seem) can make a big difference, especially if you've got little kids.
One last thing: without wanting to make any sweeping or offensive statements, I suspect that the type of bloke who's prone to getting himself into strife due to working with 20ish girls in skirts, would get himself into strife even if he wasn't in this job - it's just that there's more oppportunity here.
Hope this helps, and good luck whichever way you go.