Girls, can you develope real feeling for someone else when your in a relationship?

Basically, the girl I like is in a relationship but she is very friendly towards me. We've become friends so that isn't that unusual but we met at work and it seems like she become attached to me in a way. We don't get to work together that often but she always happy to see me and I to see her. We have inside jokes and I love spending time with her but I can't do anything as she has a boyfriend already and I respect that. So is she just a good friend to me or is it possible she has some feelings.
Girls, can you develope real feeling for someone else when your in a relationship?
Post Opinion