Indeed, big secrets in relationships are in my experience often problematic.

So are misunderstandings, which don’t have to become big problems if they’re nipped in the bud. What if she slowly began to become “suspicious” that her husband was attracted to men sometimes? What if she falsely connected that to a probability that he would be unfaithful? Getting it all out in the open beforehand could convert those “suspicions” into shared, positive observations about life and beauty.