X and Y know each other at work.
X is extremely laid back, yet has interests, usually sports oriented. X meets Y sporadically, but always has Z around when he sees Y.
Y always liked X and can barely contain herself when she sees X. However, whenever she sees X he is always with Z. So she can't really get a word in. Y first noticed X because of some endearing physical abnormalities, which don't seem to phase X at all. Combined with the laid back attitude, it makes X seem carefree. Y piles X with smiles and laughter, and she tries to touch him whenever she can, especially when Z leaves for a few moments. X probably notices but doesn't act like it at all. He doesn't seem to mind, but Y can't seem to tell if he cares either. In the meantime, Y is concerned that she looks weird to Z.
Y learns that X is also involved with cancer research, and that his abnormalities are a result from birth. Which Y finds even more adorable.
this sounds like an asymmetric relation..