The love i cant have

Hey 👋🏽

So i just need some advice other then from my best friend. To make the long story short i was real good friends with this guy. Then one thing lead to another and feelings started to get involved on both ends. Now the thing about it is he already has a girlfriend he lives with, but does not want to be with (so he claims) Its been a year since we “caught feelings” and now i dont know what to do, i gave him until March2018 to decide whether we continue on or end it and be friends.. He wrote me a sweet letter telling me he loves me and sooner then i actually think this situation will came to a decision and don’t get “blurry” on him to stay focus.. I don’t know what to think or feel