Does my work-dating experience above represent the “norm”? I don’t know — It all depends the person. That was part of the point; if your fiancee is trying harder than a singleton was, then her job is definitely not the problem.
It still takes effort to meet someone as a flight attendant. Quite a lot, actually. If your partner can meet someone up there, then they can meet someone walking down the street. When you break it down, either you trust your partner or you don’t. If you’re struggling in this area, look to the relationship and/or yourself and try to address it there. If you convince your partner to leave the job they love, they may resent you. And guess what? You’ll still feel insecure.