I appreciate all of the thoughtful replies here. I understand that this isn't polyamory. For me the excitement is the pleasure she would get and enjoy. If she isn't doing it for herself, then what is the point. I don't want her to do this just for me.
I would like to see this as driver to more intimacy, sex, and togetherness for us.
As I said I make it clear that I don't mind her flirting with and enjoying attention from other males, I encourage it. I make a point of telling her to enjoy herself and her free drinks.
She has also responded during sex in a couple ways. Once on a vacation to a resort she headed up to our room alone while I stayed with our child down at the pool so she could take a nap. We came up an hour or so later to find her in bed naked and asleep. After putting the baby down for a nap I joined her in bed and she woke up, we started making out. I was telling her how beautiful she is and how sexy it was to find her in bed naked. She said something to the effect that perhaps another guy already beat me to the punch. That really charged things up. I told her I hope that was the case that she enjoyed herself. I imagine us being at the beach or pool, she meets a guy she finds attractive and then seeing her take him up to our room alone. I go up a while later to not only find her sleeping naked in our bed, but an odor of sex and stained sheets along with it.
Recently during sex I told her how the idea of her taking a lover and enjoying herself made me hot. She then went on to say, oh you mean my "Portuguese Lover" and we both went on from there a bit about him. She was laughing while saying this thinking I was silly.
So she has started to play along somewhat and seems to like pushing my buttons.
I will continue to let her know the door is open.