This is right on. And it counts as emotional cheating 100%.

Dont forget the part where she is now HIDING everything about him.

At this point, those trust issues aren’t going away no matter what happens. I’d put money on it.

The trust is already broken. She’s deleting messages because she doesn’t want to upset him. In other words, she doesn’t trust him to react properly. And that’s the best possible world. More likely is that she knows there’s a good reason for him to react badly to those messages, and she just doesn’t want him to do that.