It would not be possible for him to tell her in advance that he will do something if he does not himself know in advance that he will be doing it.
Consider the following very likely scenario:
A husband takes the dog for a walk every Sunday. (I hope he does, or someone does, otherwise poor dog.) Sometimes his wife goes too, sometimes she doesn't. When she does, they are an obvious couple and nobody else walks with them (given her apparently possessive attitude and her tracking his phone I suspect she may give out "don't even look at him!" signals very loud and clear); when she doesn't, he will walk and talk with other people if he happens to meet one he knows. One of these other people, who also takes their dog for a walk, is work colleague of his who happens to be female.
Since he doesn't know on any given Sunday whom he may meet when he is out, he cannot tell his (sleeping) wife in advance whom he is going to meet. She has not said whether he tells her he has ever met anyone else, in fact she has not said anything in answer to any of the very relevant questions she has been asked here.
The wife first complains to a bunch of strangers that this happens intermittently (ie, not as a regular thing, nor frequently) and then after reading the reactions her complaint gets, realises that she might just have made an almighty fool of herself and been very unpleasant about her husband, and says no more on the subject.