Advice for getting over a crush

Okay, so I've got a major crush on one of my coworkers (For clarification, I'm a girl in college, and he's a year or two older than me. Workplace is the only place we consistently interact). He's good looking, funny, easy to talk to, and we're into the same nerd stuff. I've never liked anyone like how I like him; I didn't think I could even like another person like that, but I still get butterflies just from seeing him, and it's been over a year now. I'm seriously hooked.
The problem is, he has a girlfriend. And from the looks of it, they've been together a long time with no end in sight. She's pretty, and she's not dislikable at the very least. I can't hate her for finding him first, but I can't help but feel so jealous.
I'm asking for advice regarding what to do. Confessing to him is likely going to put a strain on our work relationship and the friendship/camaraderie we've built, plus I don't want to actively interfere with his relationship life. I'm not even sure if he likes me the way I like him. But I can't help but feel so stuck between being happy for him and who he's with, and holding out hope that I have even the slightest chance with him. Do I give it up, or stick it out?