The Board of Immigration Appeals has determined that the proposed particular social group of "married Mexican women who are unable to leave their relationship" is not cognizable because it is circularly defined and lacks particularity. The Board also held that a lawful marriage cannot be presumed merely because two people cohabited or had children together.
The Board vacated the grant of withholding of removal and remanded for further consideration of CAT protection. The Board found that the Immigration Judge had relied on overruled precedent, made insufficient findings regarding whether the respondent was legally married under applicable law, and clearly erred in finding that the Mexican government was unable or unwilling to protect her and that internal relocation was unreasonable.
The full text of Matter of V-A-B- can be found here: https://www.justice.gov/eoir/media/1439986/dl?inline