Disaffected Mormon

Ex-Mormon refers to a disaffiliate of The Church of Jesus Christ of Latter-day Saints (LDS Church) or any of its schismatic breakoffs, collectively called "Mormonism". Ex-Mormons, sometimes referred to as exmo, typically neither believe in nor affiliate with the LDS Church. In contrast, Jack Mormons may believe but do not affiliate; and cultural Mormons may affiliate but do not believe. The distinction is important to some ex-Mormons, many of whom see their decision to leave as morally compelling and socially risky. According to 2014 Pew data, around 1/3 of adults raised LDS are now ex-Mormon (up from around 10% in the 70s and 80s) and only 25% of young adults raised LDS are actively involved. Many ex-Mormons experience troubles with family members who still follow Mormon teachings. Aggregations of ex-Mormons may comprise a social movement.

Most ex-Mormons leave Mormonism and the LDS Church because specific intellectual or spiritual reasons have led them to a conviction that the religion is false. The foremost reasons are disbelief both in Joseph Smith as a prophet and in the Book of Mormon as a religious and historical document. Reasons for this disbelief include issues with anthropological, linguistic, archaeological, and genetic evidence against the Book of Mormon in the New World. In addition to rejecting the Book of Mormon for such reasons, the Book of Abraham and other Mormon religious texts are rejected on similar grounds. A study of 3000 people who were formerly affiliated with the LDS Church recorded that 74 percent of respondents cited a disbelief in church doctrine or theology as major reason for leaving the church, but only 4 percent of respondents cited conflict with other church members as a large factor in their decision to leave. Also, just 4 percent claimed that a significant reason for apostasy was dissatisfaction with the rules of conduct professed by the LDS Church. This corroborates the assertion that many Mormons are satisfied with the communal aspect and attributes of LDS Church life.

...
Wikipedia