Mormons follow a “Law of Chastity.”

"The Church of Jesus Christ of Latter-day Saints teaches that all sexual relationships outside of marriage (defined as the legal union between a man and a woman) are sinful.  If your date has been an active member of the Church who is following these moral guidelines, then she will not be willing to involve herself in a sexual relationship with you.  She will be oh-so-grateful if you do not pressure her to discard those values.  If you do end up having sexual relations, she will feel guilty, and it will affect your relationship, you can count on that.  She may decide to repent while the relationship is still going, and that will be a tough experience for both of you and may doom the relationship, while she moves ahead spiritually and sets her “sinful” past behind her, you included.  Discover the joys of a non-sexual relationship and find sincere ways to show affection without sex.  It’s not only possible, it’s much more fun.  Sexuality is the enemy of romance, and romance is amazing."