While Megan has previously spoken out to admit she's "hurt and heartbroken" by the situation, this evening will be the first time we hear Pete talking about what he's done.
It all starts to unravel for the couple when Danielle Armstrong tells Megan in Marbella that she's heard Pete has texted other women.
After hearing that bombshell, Megan confronts Pete on the beach in a massive showdown.
Pete then decides to return to Essex, where he meets up with best pal James 'Lockie' Lock to talk about everything that has happened, and expresses his regret at having hurt Megan by sending the messages.
It's the first time Pete has spoken publicly about the texts as so far he's kept silent on social media.
A source did tell Reveal last week: "Pete never actually cheated, he was just extremely silly. He feels embarrassed and is gutted he's hurt Megan. But, if anything, this has really made him realise how much he loves her, and he's doing anything he can to make it work and prove himself to her."
Meanwhile, while Pete seeks advice from Lockie, Megan - also back in Essex - turns to her younger sister Millie for support.
Later on, Pete decides to visit Megan and try to explain the situation and reconcile with her... but it seems Megan is not quite ready to forgive him for the betrayal.
Megan confirmed the texts in a series of Snapchats to fans last week, telling them earlier this month: " I actually found some messages on Pete's phone a few weeks ago and they weren't good but I thought I'd give him another chance, because I feel like everyone deserves a second chance.
"And the way that he was speaking to me was that he was really sorry and didn't mean it. Like, obviously it's not right that he was messaging other girls but he told me it was just innocent flirting."
"That a boy that I thought loved me and I loved could be with me and doing that at the same time... It's f**king hurtful and heartbreaking. I just wish none of this had happened really."
TOWIE airs Wednesday at 10pm on ITVBe.
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