I need some brutally honest answers, how important is love?

I think you would be making a huge mistake by marrying this man. Just because we love someone, doesn't mean they are the right person for us. Part of marriage is your future goals and dreams together. You have an idea of children, building a life together. Where does his lack of ambition fit into that? You should have common goals and means of getting there. Otherwise, it's just you in love with the idea....not the man!