I honestly do not know what I gain by checking this exgirlfriend out every day. It's like if I know every detail of her, then there won't be any surprises. I guess that doesn't make much sense to anyone not living through this.
I have been there. I used to check my husband computer all the time. I know how easy it is to get obsessed with something like that. The thing is that it isn't doing you or anybody else any good. You are spending all of this time working yourself into a tizzy.
I do find out he is doing this by searching his computer. He lies to me about doing it, so I search. It validates my anxiety. I am not living in a fairytale. I need to know the truth in order to know what to do each day.
What choice does he have? How would you react if he told you the truth? I am assuming that the person he was married to for 23 years is the mother of his children. Is he looking at her stuff because he is looking to see if there is anything about the kids?
Are you planning your life around him and what he is or isn't doing? What kind of life is that? If you went on his computer and found nothing, would you still be anxious or would you think that he had learned how to hide things?
A lot of people here have been through things similar to what you are going through. At some point, the only way for things to improve is for you to start living your life and not be so focused on him. It sounds like your life centers around him and what he is or isn't doing. Read some of the lessons to get a better understanding of his behaviors as well as yours.