A woman shared texts proving her boyfriend was cheating in a TikTok video. Photo / TikTok

A Sydney woman has shared the text messages that "proved" her boyfriend had been "cheating" for half of their relationship.

The 18-year-old woman, who goes by the name Maddison on TikTok, posted a video of the messages she discovered her now ex-boyfriend sent another woman on Facebook messenger and Snapchat.

As a result, Maddison then contacted her, sharing the conversation that went into details of the year-long-affair.

One brutal message sent by Maddison's ex to the other woman implored her to take their conversation to Snapchat so his "scary misses" couldn't find it.

"She's just f*n psycho and gets cut when I talk to girls," he wrote.

"That's why I gotta break up with her," it read.

On Snapchap, things heated up between the pair, with the man asking her for a promiscuous photo, writing he was "disappointed I didn't get to see a photo of you turned around" and adding he would "expect one tomorrow hottie".

In another savage stab, he says he has to go because "I've gotta see my girlfriend", before making a nasty remark about it.

Maddison says she saw the messages after "someone else told me what had been happening" and she confronted her boyfriend "who finally admitted he had been cheating".

She then contacted the other woman to ask for "the truth" who told her other half had been "messaging me constantly, flirting and asking to f**k".

"I'm sure you get the rest," she said, adding the matter was between "you and your boyfriend".

Maddison then cut to a clip of her sobbing in what looks like a bathroom, captioned: "I'll never be the same person. I am completely broken."

The video was only shared to TikTok on Tuesday, but it has already attracted a huge response, including a tidal wave of support for Maddison.

"Oh girl, I am so damn sorry but please know that this is not a reflection on you," one said.

"Dude isn't worth it. Trust me, you will be so much happier once you actually let him go. You are amazing he is just not good enough."

"You're not broken and you are still the same person. Take your time to heal and then move on," another said.

"My heart broke reading those messages. Trust me girl, there are better men out there," one woman assured.

Others shared their own cheating stories to reassure her she would feel better soon.

"I've been through this in a past relationship. You dodged a bullet," one said.

"I know how you feel, literally the worst pain, but time heals all wounds," another wrote.

"The worst part is when everyone knows apart from you. I am 6 months out of a relationship where I was cheated on for 1.5 year, it gets better," one woman added.

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