The basketball player has been accused of cheating on his girlfriend Khloe Kardashian - with whom he shares daughter True, 10 months - with the 21-year-old model and the duo had reportedly decided not to tell anyone about what happened between them.
A source told People magazine: "It seemed she had an agreement with Tristan that they would deny hooking up if they got caught. He said no one would find out. Jordyn was shocked when the family did find out and confronted her. Jordyn acted very distraught.
But the family feels that she is mostly upset that she got caught."
Tristan and Jordyn got close when they went with a "group with mutual friends" to see Drake and went back to Tristan's for an after party.
The insider previously said: "Tristan and Jordyn were definitely hanging close to one another and were being very flirty. Tristan had his arms around her at one point. Jordyn stood by him the entire time they were out and he was laughing and smiling at her.
Jordyn stayed at Tristan's house partying with him and his friends until the early hours of the morning, and they were very touchy. They sat together on the couch and were talking and cuddling for hours. They had chemistry the entire night and everyone could see it ...You could tell they were into each other."
Jordyn was told to move out of her best friend Kylie Jenner's house whilst she decides what to do next as she is shocked by what happened too.
A source said: "Kylie is extremely upset about everything that is going on with Khloe and her best friend Jordyn. Jordyn is a sister to Kylie, and she's extremely shocked this could happen, as is the whole family. Kylie is trying to get all the facts before she makes up her mind, but for now Jordyn isn't staying at Kylie's. Kylie needs her space and also wants to respect her sister Khloe. The future of their friendship hangs on the facts."