Javier, I posted the above and realised that I had not adequately answered your question; I probably had more to say:
"In other words, what's the attitude of a woman towards aging and marriage?"
I think that, when a woman considers herself in a 'happy' marriage, in a stable relationship, the discovery that her husband is unfaithful, and with a younger woman, has that effect of devastation. I remember a movie from the 80s entitled, "An Unmarried Woman" in which Jill Clayburgh plays the role of a wife in such a situation. Here's a link to info on that movie:http://en.wikipedia.org/wiki/An_Unmarried_Woman
They'll be a gamut of emotions that that woman will go through. The first emotional reaction could be denial, which is a strong emotion in itself - there follows other equally as devastating emotions.
And as for the younger woman, well the forsaken wife would, I think, have pause to compare herself, remembering what it was once like to be young and have that attractiveness of youth still on her side. Also, an older woman has much life experience and another thought/feeling she could have is that "how would this younger woman feel if it happened to her
?" Women have the empathy of their gender, so why does it lack in the mistress?
Also, the married woman has had the stability that that marriage has provided for all the years previous. Suddenly, she's thrown into instability of security - and looking at herself in terms of her own desireability and attractiveness. For some it's a crisis in which to grow and move on. But others will end up spiralling in resentments and depression.
I feel it's so important for the individual to care for their personal self-esteem - and continue personal self-inner growth - regardless of single or married, gender and age. Women could be regarded as the more vulnerable because of their greater emotional make-up, and for the fact that they may be home-makers and not be the wage earners.