Some amount of physical and romantic acts in pre-marriage period is normal. However, it should be limited to hugs and kisses. Intimate physical activity (which includes intercourse) should be avoided and kept as a special gift to give each other. This will add an excitement and eagerness to your marriage. While you involve yourself in soft physical activities (like hugs, kisses etc.) be sure that you will not slip into further. He may try to proceed (as a part of male nature) but you need to control him saying you have decided to give that as a special gift after marriage. If he does not understand this melodramatic approach then you need to talk seriously on this issue, clarifying that you do not believe in crossing the limits before marriage.