Cherchez la femme? I personally cannot think of a single case of a husband leaving his wife without there being another woman involved. Not one. And I’m pushing 60.
My friend’s husband “hasn’t felt the same for a long time” and asked for a divorce. He is adamant there isn’t anyone else. She is desperate to believe him and hopes he might come back. And he might - but there’s someone else I reckon, cos there always is.