I use to be attracted to married men and they to me when I was single. I think, for me as a single woman they felt "safer" because they were married. There is a good, solid barrier that can be used if necessary to make them go away. I imagine for married men there's an attraction to what is "free" and doesn't/"can't" make demands on him? It's kind of like a kid proclaiming, "You're not my mother!" The barrier goes both ways and can be used in an "Oh, you/I must have misunderstood!" way to get out of "difficulties". But it can also be a lonely or sad/difficult time because of the "cost" of crossing the barrier and how rarely it is crossed, even when one sincerely wishes it to be.