Celibacy in Buddhism
Celibacy is an important precept in some Buddhist traditions. Lay Buddhists, or "householders," are allowed to marry and to form relationships as long as they don’t commit adultery and don’t harm others in the course of sex. Buddhist monks and nuns are sometimes required to remain celibate while in the monastic community or Sangha. Not all Buddhist monks and nuns however are required to be celibate, as seen in some sects of Korean Buddhism and in all Japanese Buddhist sects.
Buddhist monks in those traditions that do require celibacy can leave the Sangha and return to lay life at any time. Then celibacy is no longer required. Buddhist monks may even leave the Sangha, try out sex as lay Buddhists (...putting the "lay" back into "lay Buddhist," as it were...) and return to the monastic life later, although they forfeit a certain amount of seniority. They must leave before engaging in sexual activity or they will lose the chance to return. A Buddhist can become a monk and leave again up to seven times in a lifetime.
In Tibetan Buddhism, the songyum was the consort ("spiritual wife") of many high-ranking lamas. Such sexual activity by the ostensibly celibate was a closely guarded secret, with only the Lama's closest associates knowing of the woman's existence as a songyum - to all outward appearance, she was just another student or nun.