Ummmm.....I'm surprised at all the rationalizing answers given here.
It's been my experience that men usually say what they mean and mean what they say. If a guy isn't saying "I Love You" back - it's usually because he doesn't!
So, unless everything else about his behavior towards you is speaking volumes about his unspoken love for you - I think it would be safe to assume that he is not in love with you.
That doesn't necessarily mean he doesn't like you, or wish he could feel love for you, or maybe he's too depressed to feel love for anyone - I don't know.
But if he was FEELING those IN LOVE feelings, he would have responded in kind.