She may have gone through his phone and saw text messages .She may have just decided that he was cheating and knew .She may have asked him and he told one big lie after another .She may have met the other woman and not recognize her .
What may she have done to know for sure .
It was not easy , coming to the conclusion that the husband I once loved dearly had betrayed me and our marriage vows , but at least I knew for sure . If you are in the same situation I was in , I urge you to check out that book .