Blac Chyna has laid down the law with Tyga --- keep your groupies and hos away from our son.
We're told Blac Chyna went nuclear after their breakup ... when Tyga began hosting raunchy pool parties with "skanky women" as their 1-year-old King Cairo looked on.
We're told they promised each other not to expose their kid to unsavory conduct -- and screwing around in swimming pools counts.
But she says there's another -- even more serious problem. She says they promised each other not to introduce King Cairo to their boyfriends and girlfriends, because if another person comes into his life and then just goes away it will traumatize him. She says Tyga's already broken that promise.
Tyga is telling friends ... maybe he's violated their deal, but she's no saint either. He claims she's been spending time with other men.
It's gotten so bad ... they're each threatening to take the other to custody court.