I can't offer any statistical evidence but my anecdotal experience is that women often take infidelity with an internal sense of failure on their part, even if their brain tells them it was completely "on him". Men seem to internalise it far less.

The need to understand "why" is more obtainable if the reason was that the husband had an undisclosed sexual attraction or preference for other men. A woman may, after the initial hurt, be able to feel a level of understanding and commission in such a scenario, but when it's with another woman there is no reason that can offer any comfort, the only small solace is absolute honesty to whatever questions she may have.

Often it opens a door for the woman to question if she could have done something to prevent it, analysing her looks, struggling with her stuff esteem etc which in turn less to crippling amounts of insecurity, self doubt and inevitable comparison.

It's quite common for women to become fixated with the "other woman", feeling a need to know about her appearance and personality. I've noted that in instances such as infidelity that women often cling to obtaining information as a way of intenally maintaining some sense of order and control whilst trying to process & make sense of a situation.

Of course this is a large generalisation and there will be plentiful exceptions but such responses are surprisingly common.