Most Helpful Guy
Accept the frigin reality, and move on. If he's gay, that means he has no (or very little) sexual attraction towards females (you included). That also means he's into boys, not girls. That means he's NOT into you, and never will be.
So you won't get him back, simple as that! Just give it up for christ's sake!
Most Helpful Girl
Let me ask you a question. What are the chances that you will start to be sexually attracted to women? Probably quite small. Well the chances that he will 'turn straight' are just as small. It's not happening. MOVE ON.