Part of the issue, family lawyers said, flows from the guiding principle in family court: all decisions are made to serve the “best interests of the children.” A parent’s rights can quickly become secondary in this setting, where overworked judges may pressure parties to settle quickly.

“It’s almost presumed that what’s in the best interest of the child is for the parent to subsume their own personal needs,” said Anna Maria Diamanti, the director of the family law and domestic violence unit of South Brooklyn Legal Services. “Your need to not be oppressed is not more important than your child’s need to have stability.”

Some who have left the ultra-Orthodox say that in recent years, the community has become more organized in how it aids the religious parent and ostracizes the parent leaving the fold.

For the parent leaving, the trauma goes beyond the private dissolution of a marriage. “Their job gets in jeopardy, their home,” said Chani Getter, a program manager at Footsteps, an organization that offers support to formerly ultra-Orthodox Jews. “If they are renting from a religious landlord, surveillance goes up,” she said. Each child, she said, is considered by the community as a Jewish soul that cannot be lost.

But Mr. Rapaport said it was conspiracy-minded to accuse the community of acting as a monolith. Instead, he said, individual parents suing for custody are relying on their large networks of relatives and friends to help make their case, as anyone would.

“It’s not that simple,” he said. “We are the most split-up community you could ever think of. It’s very rare to get people together for one cause. Everyone marches to their own drummer here; it’s like herding cats.”

Ms. Weisberger married her husband, Naftali, in 2002 when she was 19. They decided to get a religious divorce in 2008 after she came to terms with her sexuality and revealed to her husband that she was a lesbian. As she came to accept herself, she also began to reject her ultra-Orthodox upbringing, which teaches that homosexuality is forbidden.