'I thought my best friend had my back. Then I discovered what she sent my boyfriend.'

As told to Ann DeGrey.

Sophie* was my closest friend and was such a breath of fresh air after I'd been ghosted by my former best friend over a minor argument. Things were just so easy between us — we gave each other a lot of support, I felt I could share everything with her and never be judged.

We were both single girls when we met, but things changed when I started dating Liam*.

When it looked like it was going to be something serious, Sophie was the first person I called. She seemed genuinely happy for me.

"He sounds amazing!" she said after I told her about our first date.

And he was. Liam was an all-round gorgeous man — kind, funny and thoughtful in all the best ways. After years of dead-end relationships, I finally felt like I'd met someone who saw me for who I was.

Sophie said all the right things — how I deserved to be happy, how I should take things slow but enjoy every moment. I trusted her with my life. She was the one person who'd always had my back. But little did I know, she was terribly jealous of my new relationship, and it wasn't until it was over that I found out exactly what she did to sabotage it.

Watch: What type of friend are you? Post continues after video.

Things with Liam were going great until, suddenly, they weren't. Out of nowhere, he began pulling away. Texts became shorter and less frequent. Calls went unanswered. Then, one evening, he showed up at my door looking serious.

"We need to talk," he said.

He told me he couldn't see me anymore. I was shocked — what had I done?

"I thought you were different, but I've got proof you've been seeing someone else behind my back."

I stared at him, utterly confused.

"What are you talking about? I'm not seeing anyone else!"

Then he pulled out his phone and showed me a picture. It was of me with a guy I went on two dates with a few years earlier. I had my arm around him, smiling, as we drank beer at a bar. The timestamp on the photo was from two weeks ago, around the time Liam and I had started talking about taking things to the next level.

I told him that it was an old photo, but I was curious about where he got it from.

"The date's right there. It's recent. I can't trust you anymore," he said.

No matter how much I tried to explain, he wouldn't believe me. He left, taking with him the happiness I'd started to believe I deserved. I was heartbroken and confused. Who had sent him that photo? And why would Liam think I'd been cheating when I hadn't so much as looked at another man since we'd started dating?

I spent weeks trying to make sense of it. I replayed every moment in my head, searching for some clue that might explain who would have done this to me? I told Sophie about it and she was quite dismissive. She said things like, "If he doesn't trust you, then you shouldn't be with him."

Then, one weekend, Sophie asked me to dog-sit while she was interstate. I didn't think twice about agreeing; after all, she was my best friend.

While feeding her dog one evening, I opened a kitchen drawer to grab a tea towel and found a small stack of papers tucked inside. On top was the photo; the one Liam had shown me. I felt absolutely sick. It was the same picture of me and that man I'd seen a few years back. But underneath it, I saw something else: the original photo, dated years earlier, before I'd even met Liam.

It hit me like a punch to the stomach.

Sophie had taken the old photo, photoshopped a recent date onto it, and sent it to Liam. Why would she do this to me? When she got back from her trip, I confronted her. I didn't give her a chance to deny it. I shoved the photos in her face and asked, "Why did you change the date on this picture and send it to Liam?"

At first, she tried to play it off.

"I was just trying to protect you. I didn't think Liam was good enough for you."

I shouted at her, telling her she had destroyed my relationship by lying to him and lying to me.

She eventually admitted the truth: she'd been jealous. She couldn't stand seeing me so happy with Liam, while she was still single. Instead of being honest about her feelings, she'd decided to sabotage my relationship.

I walked out of her house that day and haven't spoken to her since.

I reached out to Liam, explaining it all to him and, thankfully, I managed to convince him that I was telling the truth. A year later, we are still going strong, and we're living together. But I've had nothing more to do with Sophie. That experience was a clear example of how, sometimes, the people closest to you are the ones capable of hurting you the most.

*Names have been changed for privacy purposes.

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Feature image: Getty.