A woman who was a surrogate for a couple said she had an affair with the father - and now she wants custody of the child

• A surrogate in British Columbia is suing the father, seeking joint guardianship of the baby.
• The surrogate said in court documents that she had an affair with the man, who's married.
• A judge who's not involved in the case anymore said the situation was "unprecedented."

A surrogate said she was impregnated by a man in British Columbia after she agreed to be his family's surrogate. Now the woman wants joint guardianship of the baby she birthed, she said in court papers obtained by The Daily Beast.

The woman, called K.B. in the court documents, also said the father, identified as M.S.B., had promised to leave his wife and raise the baby with K.B. but never followed through. He has disputed the claims and the details of the affair.

British Columbia Supreme Court Justice Warren Milman said in the court documents, dated June 30, that it was a "highly unusual" situation with "no comparable precedent." Though an official custody agreement has not been solidified, Milman, who's not involved in the case anymore, said he thought the child should stay with M.S.B. and his wife for stability reasons.

After a failed IVF attempt, the man naturally impregnated her, the woman said in court documents

K.B. met M.S.B. in spring 2014, and they began an affair, she said in the court documents. Over the next two years, K.B. said, M.S.B. impregnated her twice, and she had abortions both times.

During the affair, M.S.B. and his wife had trouble conceiving, so K.B. offered to serve as a surrogate through artificial insemination, she said. They traveled along with M.S.B.'s wife to India for IVF, but it failed, K.B. said.

The court documents showed a signed surrogacy agreement between both parties. K.B. denied signing it.

When IVF failed, M.S.B. suggested natural insemination, or having sex with K.B., so that she could get pregnant, K.B. told the court.

K.B. said M.S.B. had also told her "he would leave [his wife] and they would raise the child together as husband and wife," the court documents said.

M.S.B. denied these claims, saying the affair started after K.B. became pregnant with the surrogate baby. They parted ways in summer 2018.

Mounting custody disagreements led to a legal battle

K.B. filed the lawsuit against M.S.B. in July 2020, saying she deserved joint custody, equal parenting time, and child support.

M.S.B. and his wife said they'd paid the surrogate thousands of dollars over their three-year relationship as she made "progressively greater demands," like a formal visitation schedule with the baby, the court documents said.

As a court prepares to hear the case in January, the married couple has denied K.B. all visitation rights.