Stella Maxwell 'Fuming' Over Ex Kristen Stewart's New Lover Sarah Dinkin

Kristen Stewart is all loved up with new girlfriend Sarah Dinkin and RadarOnline.com can exclusively reveal ex Stella Maxwell is fuming!

“They made a pact not to rub it in each other’s faces by dating anyone else publicly for a while – but Kristen couldn’t help herself and decided to go public with Sarah almost straight away," a insider snitched.

As RadarOnline.com readers know, Stewart,28, and Maxwell, also 28, had been bickering for a while over a range of issues, but they always found a way to patch things up so the supermodel is said to have "been knocked sideways at how brutal Kristen’s been."

Despite their disdain for one another, the duo continue to have run-ins. "The worst part is that they share a lot of mutual friends," the informant revealed exclusively to RadarOnline.com, "all of whom are having to take sides because the girls won’t speak to each other at all now."

One pal snitched: "Don’t be surprised if Stella makes a cheeky play for Robert Pattinson or other revenge type stuff – she’s that angry!"

As RadarOnline.com previously reported exclusively, the former Twilight star is growing deeper with new gal pal Sara Dinkin.

“Kristen was burned by Stella very badly,” a source told RadarOnline.com. “She really wants nothing to do with her at this point because she knows now that Stella was using her to make a name for herself.”

Stewart and Maxwell haven’t been an item since at least October. Insiders told RadarOnline.com exclusively Maxwell became “obsessed with fame”  and was taking advantage of Stewart. “Everyone told Kristen that, but she didn’t believe them.”

Less than a week after their split, Stewart was seen rebounding nicely, packing on the PDA all over L.A. with stylist Dinkin.

The new couple even spent the holiday season with one another, further cementing their newfound love.

“She is really having a lot of fun with Sara,” the insider added. “They definitely are picking things up and spending every day and night together.

“Kristen joked to her that they will be living together in no time.”

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