Relationship? problems?

Okay so i like this guy.... and so like hes dated a lot of people like 7 since middle school but hes not a player or anything like hes never cheated or anything and hes super funny and cute and were in a lab group together and we call each other bestfriend and poke each other a LOT and mess around but there is one small problem..he has a girlfriend and like shes kinda my friend like not a best friend but a close aquatiance to the point that she doesnt know that i like him but i like him like a LOT and they dont even go good together so what should i doo!? We have like an awkard relationship like we call ech other bestfriend and like touch and poke each other alot and talk but like we don't have each others phone #(im pretty sure he lost his) and like yeah and im totally clueless and just frustrated that there dating and just idk so help!