This is what I don't understand with people. Everyone's first reaction was "you shoudl not have read his / her phone". Well, I am sorry but if I read my hubby's phone and saw flirty texts, then I would not be ashamed to admit I was snooping. Lets face it, if Harry31 didn't snoop in the first place, then he would never know. He looked for evidence and found it, and if she was honest in the first place, then there would never be anything to find, would there?
Harry31, you should confront her, tell her you had your suspicions and looked at her phone - it is her that has explaining to do, not you.
All the best.
x