Hmm.. I havent been in your shoes but I do have an opinion. Sometimes knowing why the woman did this isnt as important as dealing with and healing through the real issues in your marriage..infidelity, mistrust, poor communication etc... Not saying you shouldnt ask or dont have the right to.. but what would knowing that change? Where you focus is so key to moving on and not getting stuck. Blame is an ugly game that is counter productive in nature. You can point fingers and blame til the cows come home but if the problems at hand are not the focus nothing will change. My hat is off to you..I would not and could not stay with my spouse if he did this to me. I would see it as an issue of disrespect in the highest order and that coupled with issues of misrust I could not see my way through to stay commited to man that wasnt so commited to me..so kudos to you for doing what many could not..staying. I just hope you can believe that he is done with this behavior and that he can prove to you that he is. Otherwise your really just spinning your wheels til the inevitable transipres.