AceShowbiz -

Kylie Jenner and Tyga's relationship seemingly hits a rough patch again. The "Keeping Up with the Kardashians" star reportedly ditched the 26-year-old rapper at the premiere of his film "Barbershop: The Next Cut" in Los Angeles earlier this week because she was apparently not happy about her boyfriend's response to her brother Rob Kardashian and her nemesis Blac Chyna's engagement.

A source close to Kylie told RadarOnline that the 18-year-old star's brother's engagement to Tyga's baby mama had "destroyed" her relationship with the rapper. When the entire Kardashian family was on a snowy trip in Vail, Colorado, Tyga posted a congratulatory note to the couple on Twitter, and Kylie was clearly upset with her beau's decision.

"All this drama really started when Tyga spoke out on social media about Blac and Rob's engagement while she was away. Kylie had specifically told him to NOT say anything about it until she did," the source said. "Tyga talked so much s**t about Blac being with Rob to Kylie behind Blac's back and to everyone else and then he goes and sends them well-wishes. It just really pissed her off!"

What made the youngest sister of the Kardashian clan got angrier was probably because she was jealous of Rob and Chyna's engagement, considering that Kylie really wanted Tyga to propose to her. "Tyga knew that Kylie has wanted him to propose to her for so long now," the insider added. "And now she is just legit jealous of her brother Rob and Blac's upcoming wedding because the whole family is going to be focusing on that and not on her!"