'I thought I'd never see my cheating ex-husband again. Then he stepped out of mum's car.'

As told to Ann DeGrey.

When my marriage ended, I was absolutely shattered. Tim* and I had been together for seven years, married for five, and I thought we were solid. Like any couple, we had our crappy moments, but I believed our love would get us through anything.

So when I found out Tim had been cheating on me, it really knocked the wind out of me.

And, to make matters worse, he was cheating with his ex-girlfriend, of all people. At first, he claimed he was "just helping her out."

She was moving into a new house and needed a hand. Then it was a few odd jobs around the place. He swore it wasn't anything for me to worry about. He said he had no romantic feelings towards her but felt sorry for her and that she had no one else to help.

I tried to be understanding.

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One night, he went over to "help her fix a broken window", and didn't come home. He claimed he'd fallen asleep on her couch and didn't want to drive when he was tired. I was suspicious, of course, but he insisted they were just good mates, and I was overthinking it.

But then one Saturday afternoon, I popped into the supermarket to grab a few things — and there they were, hand in hand, completely at ease. I couldn't believe it!

My worst fears were confirmed.

I walked out of the shop and cried in the car park for half an hour. When I confronted him that night, he didn't even deny it. He just said he'd "fallen back into old feelings" and wanted to try again with her.

So our marriage was over! It took me a long time to recover. I kept things civil with Tim when I had to, but we weren't in contact beyond the occasional legal form.

Eventually, I heard through the grapevine that it hadn't worked out with his ex after all. They were fiery from the start, on-again, off-again, and it sounded like it had finally burned out for good.

I didn't care. I was done.

Then, a few months ago, my mum suggested a short family getaway. "Just a few days on the Central Coast," she said. "Some sun, some rest. You need a break." It sounded lovely.

Life had been stressful, and I was finally in a good place. A little holiday with Mum and my sister sounded like what I needed.

We drove up separately. I arrived first and checked into our Airbnb. 15 minutes later, Mum pulled up and, to my horror, out of the passenger seat came Tim.

I thought I was hallucinating! Then he waved like it was no big deal and walked up the steps with his suitcase. I looked at Mum. "What is going on?"

She looked nervous. "I was going to tell you," she said. "But I knew you wouldn't come if I did."

No kidding! She went on to explain that she'd stayed in touch with Tim after the divorce.

That she still saw him as family and didn't like how things had ended.

She was "embarrassed" that we'd split up and thought maybe, if we all spent a few days together, we might talk.

I couldn't believe what I was hearing. I told her he had cheated on me, and now she had completely betrayed my trust. I'd worked so hard to move forward, and here she was dragging me backward.

As for Tim, he didn't say much. He just stood there awkwardly with his bag while Mum did all the talking. I told him I didn't want to see him, didn't want to speak to him, and certainly didn't want to share a house with him for the next four days.

Then I grabbed my own bag, walked straight back to my car, and drove home.

I've forgiven my Mum, but I'm still very disappointed with her actions. She has told me several times that she was just trying to help, that she thought she was doing something good. But I don't see it that way.

She dismissed my pain and made a huge decision on my behalf without telling me.

I know her heart was in the right place. She loved Tim like a son and couldn't accept that it was over. But the thing is, it was over! And I didn't need to be ambushed on a supposed holiday to be reminded of everything I went through.

After a few days of feeling hurt, I did something impulsive: I booked a solo trip to Fiji. One week, just me, no surprises. I leave next month, and I'm counting the days.

If there's one thing this sad experience taught me, it is how important it is to have boundaries and to protect your peace. Especially when the people closest to you forget.

*Names have been changed to protect privacy.

Feature Image: Getty. (Stock photo for illustrative purposes only)