Stop snooping. It just hurts you, you have confirmed maybe. However the truth always comes out. Prepare yourself for the worst and hope for the best.
Alright, here it is. So you have an "A" thought, you see a cell number and assume the worst. Then you react with a "B" behavior. Oh ya, well screw you W. That leads to a "C" conclusion that you don't want. Next time you have an "A" thought, lets jump to "D". D is, you don't really know, I never walked in my W. I now know from her confession that it did happen. However, what does ABC get you, but upset and reactive. Tone down, take it slow, let her explore her problem and just keep DB'ing.