Men typically are insanely simple. When he tells you something as plain as this it is exactly what he says.
It is possible that he loves you but doesn't want to be married. I personally don't think that his position on marriage has anything to do with you personally. He most certainly just simply doesn't want to get married.
is that love or being used? the question could have been: my boyfriend has used me for 1.5 yrs without proposing marriage, should I leave him? take care.