In the summer of 2008, Sarah Irish Nicholson’s well-ordered Mormon life was unraveling, and she needed someone to talk to. Nicholson’s husband of 13 years, whom she had loved since they were madrigal partners in high school, told her he was gay. Latter-day Saints in her West Valley City ward kept saying gay-rights advocacy was Satan’s work, she says. Though the couple remained together at first and honored their marriage vows, several local Mormon leaders were not only unsympathetic, they also were openly hostile to the news. Nicholson, who still was clinging to her LDS faith, wanted a place to share stories, cry, laugh and encourage. She turned to a national website, straightspouse.org, an umbrella organization for some 55 similar groups. But she felt many of those posting there were bitter and just wanted to vent. So she launched straightspouses.org, which invites people to join a private Facebook support group. Last fall, there were 14 members. Now there are 45, mostly Uta...