The movie was done by 10:00. Only reason I mention this, is that pattern for OW, from what I have noticed and my best guess/assumptions is that she gets off work between 10-11, as that's when the normal time for the "ding-ding" chime will come in on his phone and he texts back a few times and then phone will ring and he will go to his room to take the call. Lately, the calls haven't been happening as much, unless they are just taking place after he goes to bed in his room. Who knows?
I would like to put a boundary in place for the texting, but don't really know how to go about it and/or approach it. Any suggestions?
Yes. Next time it is between 10-11:00, and he's getting texts, and his facial expressions and body language tell you that it's OW (you're a pretty perceptive woman, AFG -- trust your instincts), say:
"I certainly hope you're not texting your girlfriend in front of me. That would be incredibly disrespectful."
And just stare at him. If it's her, he'll say that it isn't, but he'll stop, and he'll most likely never do it again.
If it isn't, and it's innocent, he will show you who it is.
