Depending on where you live, his parents' attitude on you two getting married without you being LDS can change - but that's not the point. The point is that we, as LDS members, are supposed to be married in an LDS temple. That is the only way we can enter the Celestial Kingdom (highest kingdom in Heaven). However, it is also alright for us to marry outside the temple (parents opinions disregarded - this is from the view point of the church). I believe that the doctrine is that God will accept a marriage as long as it is legally binding in the country/state/etc. where it was performed. However, He only considers it binding during THIS life, not in the life to come. We believe that, for marriage to be truly eternal, it must be performed in the temple.