Infatuated with coworker/friend for years...

File: sadnesssss.jpg (39KB, 627x346px) Image search: [Google]

39KB, 627x346px

Hey guys. I need some help here...
I graduated 3 years ago with my engineering degree and landed a job far from home shortly after. Moved to a place where I knew no one but with high hopes I would get a new pep in my step after the pain of college. Shortly after starting work, I found and started being included in a workgroup of other newly hired engineers and I became closer friends with 4-5 of them. One is this girl.
I knew I wanted to spend more time with her right away. We are very similar and I am never nervous around her. She is shy but outgoing. Great sense of humor. Patient. Smart. I then find out she began dating another guy within the 4-5 person group. Heart somewhat broken, but I honestly was okay just being around her, even in the group setting, as it was x100 better than sitting home alone. Over the years, I've been slowly breaking down though. I read to try to break away from the group to make things easier. Also read never to tell either him or her what I feel. We have spend solo time together many times and it is some of the best times I've had in a long time. I've sort of converted this frustration into a drive to workout and improve myself in many ways. I will eventually return home and fantasize about telling them both shortly before leaving, dreaming that she will tell me she felt the same. Sorry for the TLDR story. I could go for hours.
Any recommendations on what I should do? How would they react if they knew? Anyone else been in this situation? Thanks.