Most Helpful Guy
Most Helpful Girl
You have to accept the fact that he's taken.
Continue to treat him as a friend
If their relationship doesn't work out , and you're still single let him know how you've always felt.
However don't put on your eggs in one basket and hope things goes wrong.
You don't know how long that will take to happen.
Look elsewhere for a guy.
Enjoy him as a friend.
Sooner or later your feelings will subside