Not to be a downer but in my case my H got a 'secret' phone to use with his affair partner. That way he could leave his phone out, I could see it at all times, check the records, and it didn't matter. BC he was using the other phone all day long at work, taking it in the bathroom at home to text, even texting in our bed after I fell asleep! (This I know bc it fell out of his pj pants pocket one night and I rolled over on it, finding it and reading a ton of not good texts...)
Just saying that monitoring her cell phone is like .0001 of the solution.....