Why does my husband fantasize about men?

Yes of course. Many of them do it. If they are not emotionally attached with their husband, and not getting satisfaction by the act of her husband. Like men ,women go to the world of fantasy and think about other man whom they like or meet and get higher level of sexual pleasure even though they are having sex with their husband. Some couple even practice this mutually to get better pleasure. In such case the name of the other persons will be uttered by each other. There is no limits to sex.