He liked me then, I like him now, what should I do?

So today I found out that the guy i like now liked me in the fifth grade, he was just to shy to talk to me (we are now in the 8th grade) I like him now, but now he has a girlfriend and he says hes in love. I know we are only 13 and these things don't last forever, so i should i go along with this until they do break up? How do I get him to like me without flirting cause im not a tramp and I don't want to be the reason they break up. But we aren't really friends but we share so many of the same views and over the past few days we have become even better of friends. I know he liked me in 5th grade for a fact because he told me. So how should I handle this, he knows a have a little crush on him.