Why is treating women well a negative quality?

This isn't necessarily a nice guy vs. bad guy question. From personal observations and questions repeatedly asked in this forum, it seems that women disapprove when their husbands or boyfriends show common decency to other women. For example, a recent question I read was from a wife who hated the fact that her husband sent a text message to a female co-worker inquiring about her health. She felt as if all of his compion and empathy should be saved for her. Are these positive qualities in a man genuine, if he is able to only focus them on one woman?