>>They may hate sex, but they do it
I don't know ANY women who hate sex itself. Perhaps the man has gotten lazier as well, in regards to sex?
>>They go to the gym...if they become a fat slob the guy will leave
Women's bodies are not the only ones that deteriorate. Are all of the men of your acquaintance perfectly fit as well? Furthermore, many women's bodies change in unexpected ways after childbirth...it is entirely normal to take up to a year post-breast feeding to recover, and that is provided that the women has time away from the child to exercise.
>>They act nice
As another woman on the thread mentioned, it is not only women who can be petty in relationships. Her "bitchy" behavior is almost certainly at least partially the husband's fault.
Perhaps the husband began working more hours, which combined with childcare, left the couple no time to be together?
It cannot be denied that marriage is hard. But it is far from impossible, and far from unsatisfactory when done properly. However, it takes work on both sides to maintain and adapt. I am not denying that the woman causes problems of her own, but relationships are rarely broken just by the fault of one person. You are probably getting a biased account because you are hearing it from the husband's perspective. Their wives may have things to say that would surprise you.