Bill, I see this same dynamic with women in their 30s, 40s and 50s as well. It's sad, but I think it's basic human dynamics. As a reforming "Mr. Nice Guy" myself, I WISH this weren't so . . . . but I'm afraid it is.
Puppy
It is true, it's human nature. We're literally built this way and there are reasons for it and women in their 30s & 40s get a boost of testosterone production during those years, they become more aggressive, assertive, and start to test the men they're with even harder than they did previously. The downside, men entering their 30s will notice their testosterone production waning, you go down while they go up - cruel joke to be sure but you can bump up your testosterone by maintain a healthy lifestyle, working out with weights. Women have instincts to test their partners during these years more than any other years to make sure that the mates they have chosen are still strong enough to protect them and take care of them - it's an ancient instinct that still exists today and will make women search out new partners and do crazy things in the process (neglect their children, leave their families, have affairs, etc.) and all the while their clueless husband is left holding the bill and asking "why has she changed, I can't understand it, this isn't logical, why is this happening, can't she see what she's doing to her family? When will she snap out of fog, she's living in fantasy land, etc. etc. etc."
Obviously men cheat on women as well, this isn't a one sided story but the example I've quoted above represents the other dynamic.
You won't get your WAW back by kissing her ass, begging & pleading, doing everything for her, buying gifts and dinners and waiting for her to stop having her affair. For all the logic that some men on this site try to spout out, does the practice above really sound logical - do you really think that this will get your wife back? If she's seeking out a more masculine mate, do you really believe acting insecure, weak, scared, sad and emotional is going to get her back?
No.
It won't.
Move on.
That will probably be your best chance at getting her back. Detach, let go of the rope, get a life, act as if, etc. Agree with her, "you're right, things will never work out, divorce is the right decision, I don't want to be with you anymore either, you should be with the other man, I'm glad that you are, because now I have a chance to find a better woman, etc."
Counter-intuitive but like most everything else on this site, doing what you feel should work rarely does, doing the opposite tends to produce results. Observe reality, don't go against it, follow reality, follow the reality of your situations, if your wives don't want you, agree with them and stop wanting them back and start moving in the opposite direction, weird but it tends to work alot more effectively than being a super loving nice guy.