Marriage and Sexuality in Mormonism
LDS views on marriage and sexuality have ebbed and flowed over time. When the Church was first founded, monogamy was held as the ideal. From the mid 1840's to the 1880's polygamy or "plural marriage" was held up as the standard. From 1890 to the 1920's polygamy was practiced in secret by some Church leaders who disagreed with President Woodfuff's "Manifesto" that officialy ended the practice of plural marriage in 1890. This is a fascinating period which Michael Quinn has documented in a wonderful essay exploring plural marriage during this time.
The Church has always taking a strong position on sexual immorality -- that is, sex or sexuality outside marriage. There have been times when the rhetoric even on masturbation was quite strong. However, "official" or high-profile statements on masturbation have decreased in the last 10-15 years.
Sexual Purity - from "For the Strength of Youth" Pamphlet
Masturbation in Mormon Culture
To Young Men Only - Elder Boyd K. Packer
Overcoming Masturbation - 1970's -- Mark E. Peterson (probably)
God Loveth His Children - Pamphlet for Mormons Struggling with "Same-sex Attraction."
20th Century Statements on Homosexuality
First Presidency Letter with Instructions Regarding "Impure" Practices - 1982
President Spencer W. Kimball Counsel on Interracial Marriage
First Presidency Private Letter on Race and Interracial Marrage
19th Century Statements on Monogamy