Quoting £egendary £ex:" He did something bad by clearly lying about it. I wouldn't trust either one of them that 'nothing happened' either."
The only thing I can see that he lied about was getting the text saying, "text if you can't sleep". He didn't lie saying where he was or what he was doing the other night. So he had her over to their house...big deal. They're old friends. How do you know the text wasn't sent to multiple people and she was hoping for a reply from anyone? She could have been bored and just wanted to pass the time. Nowhere in the OP does it say he cheated, and by assuming the worst, they're going to have problems in their relationship. Ya, he should have told her who was texting in the middle of the night...but if he wasn't planning on continuing with a conversation with her, he doesn't need to tell her. I think OP pretending to be him is far worse than him not telling her who was texting.