Hack reporter Jo Lauder sat down with 19-year-old Eliza. This is Eliza's story:

When I was growing up, nothing struck me as unusual with my parents and their relationship: I thought they were deeply in love. They might have argued a bit, but they seemed happy.

That all came to a crashing end when I saw my dad making out with a family friend while were away on holidays. I didn't know what to do, so I asked my mum and my older sister what I'd seen. They told me I was lying, which confused and hurt me more. I knew what I'd seen, didn't I?

A few months later the truth came out: Mummy and Daddy love each other very much, but they're going to start loving other people too.

What?

I didn't understand. Would this mean they would sell our farm? Would they split up eventually?

I remember crying; yeah, I did a lot of crying.

The news didn't bother my sister - she was older and only cared about her own life and dramas, the way most teenagers do - but for me as a nine-year-old, it felt like the stability and security it my life were being taken away while I was still learn what my family foundations were.

I remember my mum cradling me, stroking my hair, and her gentle words. She thought it was important for me to let it all out so I wouldn’t hold in the trauma. Looking back, it must have been a fright for her too; was she wrong to let her baby hurt like that?

My mum tried her best to explain it to me, how they believed in free love and wanted to be open to loving and seeing other people. For me, I thought if they loved each other they shouldn’t need anyone else: I still think that.

My parents told me everyone is unique and each new partner can give you something your partner can’t, but I still believed in the idea that you can be content with one person and don’t need to greedily.

My feelings towards polyamory haven’t changed in the past decade. I’ve seen my mum’s raw emotions after breaking up with another partner and wondered why she’s doing it, and in my teens I put down boundaries for their poly lives: don’t bring your partners into our home. I have friends who are polyamorous and I tell them what I think, but I see it as different to my parents because they don’t have kids in the mix.

Mum thinks a lot of my reaction comes down to the way I found out, how I walked in on Dad with another woman and the shock and confusion I felt.

She doesn’t regret telling me, but I know she deeply regrets how much it hurt me.

In the ten years since I was first rocked by my parent's new love lives, I’ve spent so much time going over my own reaction, and why I’ve never liked my parents being poly.

One of the things that hurt me the most is how it skewed my parent's priorities, as juggling multiple lovers and the permission to hook up outside their marriage takes up precious free time. I felt like we always came off second-best.

I told my mum that recently, and I could see it hurt her deeply, and now she is more vigilant about it and ensures that her kids are her top priority. She’s told me she felt guilty every time she went out, and she thinks she was very present and attentive as a mother, so my criticisms upset her.

I’ve always been very honest with my parents about what I think, and in turn my parents have done their best to be discreet about it and not hurt us anymore.