What does it mean when a guy says he don't think he is ready for a relationship yet?

I stayed with this guy for 3 nights in a row. He snuggled with me but didn't try to have . I have known him for 3 years now and he stares me in the eyes when ever I see him. His family really likes me and keep teasing him about me and telling him how nice of a girl I am. So I finally got the guts to ask him what was going. This is what he said I don't know right now, i don't think I'm ready for a relationghip yet, can we just be friends. then he said I'm sorry. I mean what the hell does that mean.