How would you view women who, while in a relationship or married, who own a "normal" instagram account, with photos of their partner and child, and other normal pictures, still like the highlights and pictures of other men? (Not celebrities, but someone from their social circle or someone nearby.)
My theory is that these women are indicating that they are fine with their current partner, but the men they "idealize" or "wanted to marry" are the ones they choose to put those likes. Additionally, they might use the "like" system to keep these men in their "categories", showing interest and potentially keeping them as a "Plan B" for the future.