I'm not happy in my relationship. What should I do?

I'm currently dating a guy whom I'm unable to fall in love with because he does not have the characteristics and some qualities that I like however, he has always treated me respectfully and he truly loves me. Sometimes I feel myself drifting from him in so many ways because I'm more interested in a certain type of guy that is opposite from the guy I'm dating. He is a great guy, he is smart, he treats me with respect and he knows how to treat his woman but, I don't think ill ever fall in love with him.other