She and Alex split awhile back, but fans only learnt of their break up when Alex revealed he is single again on Made In Chelsea: South Of France. He had told his co-stars he'd dumped Nicola by text, and later went on to confess he had drunkenly hooked up with Olivia Bentley early on into their French getaway.
Nicola, meanwhile, has now said she will not be getting back together with Mytton, labelling him "gross" after learning about his night with Olivia.
Speaking to new! magazine, Nicola said it had been "upsetting" to hear Alex had moved on so quickly.
She said: "It was upsetting but then I laughed about it. He's gross, a vile human. I would never lower myself to getting back with him. I hope he finds whoever makes him happy. I thought I was pretty good, but obviously not."
Nicola had appeared to react to Alex and Olivia sleeping together, shortly after it aired on MIC's new spinoff series. While she didn't directly comment on Alex's actions, she did suggest she was "horrified" by them by liking a fan's tweet.
They had urged Nicola to "move on" in their tweet. It read: "@NicolaMHughes Just seen the new #MiCSOF - horrified with mits actions really liked u two as a couple!You seem a lovely lass #moveon #idiot."
Viewers, meanwhile, saw Alex admit that he regrets sleeping with Olivia so soon after his split from Nicola.
He had told Olivia that he was "annoyed" at himself for doing so, to which Olivia replied: "Breaking up with somebody and jumping into bed with somebody else looks savage."
Alex then said: "I do still have a lot of feelings for [Nicola] so it makes it a bit tougher."
Olivia reassured him that it wasn't a big deal to her and told Alex: "It's sex. I know you want to respect Nicola, but I don't think you should work yourself up about all of this. It was a drunken stupid night, a lot of people do do it."
He and Nicola had been dating on and off for two years.
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