Just my own take-
they are ignoring their wives (who likely don't share their cycling interests), they're feeling bored, restless, and self absorbed. They are dumping their 'angst' on you with a little hope in the back of their minds that they will get you interested in them. I'm betting that most of them have crushes on you, or at least fantasize about being with you. You are physically fit and very pretty, after all. They wish their wives were more like you.
I guess both men and women can suffer from this crisis, which is just a fear of getting old and losing one's sex appeal.
Since the beginning of time men in mid-life crisis have 'poured their souls out' to nearby lovely younger women in the hopes of attracting one for themselves. If they really want to solve their problems, they will pour their souls out to their wives and to a good therapist.

You just have to be a bit firmer with them about not being available to help them sort out their problems. Maybe you could approach it with humor and tell them it's getting to be a problem with a whole bunch of them confessing their angst to you. This might keep it light and make them laugh when they realize it's not just them.