Is it a bad idea to date my best guy friend of 5 years?

I really like him. We've known eachother for 5 years. We're really close and we see eachother almost everyday. He knows I really like him, but we came to the conclution that it would be the same if we dated and if we were just best friends. I was the one who brought it up, but hes not clear with is fellings. Hes a really tought guy,since hes been through a lot in his life. I just dont know if its a gooa idea. If not, then how do I get him out of my mind??? Please help.