What's so implausible about The Bridges of Madison County is not the story, but the notion that two lovers might find a love so deep as to last their lives- and do it in a weekend. It's a fantasy, but one that women have found delicious, because reality returned at the end: the woman refused her lover and went back to being a housewife. The love story is a fantasy that, at the end, graciously returned to being a fantasy.
Genre romance novels have always fascinated me. The heroine is often imprisoned, humiliated, beaten, whipped and even raped- all this by the arrogant six-foot lump of muscle and testosterone she somehow can't help but love. All of this is gussied up in the florid language of such novels, and the hero is always as pretty as his victi- excuse me, heroine. These novels are immensely popular though (the only genre that is consistently and extravagantly profitable) but what redeems these whippings and rapes is not the fact that the perp is blond, six-foot, to-die-for. What redeems them, what is most appealing, is that it is all fantasy.
Fantasy. There is a profound difference between "what if" and "if only." Fantasy is an experience in itself, sought after for itself. It isn't a frustrated wish, although it can certainly contain a wicked taste of "if only." Fantasy is fantasy, an experience in itself, and as such, it can enrich anyone's life. Florence in Bridges returned to reality after her fantasy fling; an implausible situation, but there is a greater truth there.
These stories likely have more in common with slasher/ horror films (another inexplicably successful genre) than it does erotica. You may find them distasteful. Read one of them if you will, all of it, and regardless of your reaction, take a moment to reflect, not on the story, but on the feelings you have towards it.
Love those you love honestly, well and gently, and for the rest of it- use your imagination!