I think this tendency has a biological basis to it. She wants to be available to the man she is attracted to. Spending time with a man she is not attracted to hurts her ability to find a man she thinks is on her level, because the men she might want sees that she is not available to them.
Your wife may be a very nice person, but I can almost assure you that she was doing the same thing with men that she was not attracted to.
I don’t even think that women are aware of what they do when they do this and I can’t criticize them for doing it, if this tendency has a biological basis for doing it.
Women are hypergamous by nature, always comparing what they have to what they feel they could get.
She may have felt that those times were temporary due to past performance, and or that perhaps she felt at those times she couldn’t do better than you, and or there weren’t really too many better men around where you were.