I'm just married and already lusting after another man?

Ok, Gonna keep this as simple as possible. Not long married and been together a few years. We work together in my husbands small business.
As our business is somewhat a social thing, we both plus work mates are out together a lot. I am feeling myself being attracted to a guy who works with us.
It all started as a bit of a joke and now I'm actually thinking of acting on my feelings. He is much younger than me, not my type and its just lust, I could never see myself with him in a relationship.

Nothing has happened, not even a kiss, just really really bad flirting.
What should I do???