Ok...you monitor that cell phone. His schedule won't necessarily have to change much if they work in the same building...that's a bit trickier. There's always lunch. Do you ever have the ability just to pop-in for lunch?
Do you monitor credit card bills/atm withdrawals? If there are excessive ATM withdrawals...where's the money going to..if they are excessive (meaning more than you think normal). Any unusual activity on the credit cards?
For me...at some point, if he says he's not having contact with her, and you don't see anything unusual you will just have to try to trust that he isn't....but keep your eyes open.
When you say he's been moody...describe what this moody behavior is like.
