How do i get my bf to pop the question?

First Thing you can not get him to pop the question. The Worse thing that could happen is you guys get married and he is not totally ready for it right now. The best thing to do is to give your expectations on the relationship. Tell him that you would love to be his wife but you don't want to just live together forever. And its only been a year and a half, that not a long time, it usually takes a man about two years to decided weather or not a girl is the one for him. Overall, don't try and pressure him into it, he will pop the question. Also tell him that you are ok with a small wedding and it doesn't matter how big it is and that you guys can always decide later about having the big wedding of y'all dreams