I can fully understand how this might happen. For instance, a woman may have been contemplating this for some time, but if one or both of them had been working there was a means of temporary relief from their unhappiness. However, once they're confronted by the prospect of being with their husband for 24 hours a day, the reality becomes too much to bear. She may have developed a social life outside of the marriage and now it is coming under threat from a husband who has his own ideas about how they should spend their time. Again, it may be that she simply cannot stand to suddenly have him under her feet. Lot of men seem incapable of coping for themselves and this will also cause frustration when he is around all of the time with extra demands on her time and energy. Perhaps she may have even tried to discuss these things with him, but they hadn't sunk in? No doubt, these women wouldn't have done this without a lot of thought.