It’s very painful to love someone who doesn’t return it in kind and degree. It’s like when someone doesn’t respond to a handshake. Your hand is out there but at some point it hurts to not have it clasped.
People in healthy marriages are honest and up front with each other. They don’t password their devices. They don’t hesitate to share their correspondence. Their relationship fills enough of their needs enough of the time that they don’t need to look for more with other people. You already know that — which is why you aren’t content to settle for the marriage you’ve got.
My guess is that your wife needs to feel pursued by other men in order to feel good enough. That’s not something you can fix, no matter how attentive you are. Your marriage will only last as long as you are willing to put up with the one sidedness — or until she does find someone who will shore up her self-esteem by pursuit — at least for awhile.
What you can do is insist that the two of you get into couple counseling. It’s possible that a counselor will be able to address your wife’s insecurities and her need to build her self-esteem by contacting other men. It’s possible there are things you are doing or not doing that contribute to her problems. It’s worth a few sessions to find out. You have nothing to lose and everything to gain.
If therapy isn’t helpful, at least you will always know that you gave it your best try.
I wish you well.