Crush on a co-worker while in a relationship

Hey Gaybros,

I'm a new barista at a local coffee shop and I have this co-worker. He's crazy charming, just my type and seems to flirt with me quite a bit. I'm smitten for him.

On the opposite side I have a boyfriend who this new co-worker doesn't know about. I've been exclusive with for about 5 months now. It's going well, he's cute, sweet and I do love him. But still find myself fantasizing about this other guy often.

I'm not sure what I'm totally looking for here. Just wanting to hear from some people who have been in this situation before and what they did, or how they reacted.