Kelly and Mia were forced to live with their step-mothers. Their outcomes were vastly different.

As a child reading the Babysitters Club book series, Kelly* always thought having separated parents would be fun – you get twice the love and twice the Christmas presents. 

But at nine-years-old, when her parents did separate, the experience wasn't quite what she expected. 

"When I was with my dad, I missed my mum, and when I was with my mum, I missed my dad," she says. 

"My mum was still very much in love with my dad and I believe they wanted to make things work for the sake of their five children."

Watch: How to support someone going through a separation or divorce. Article continues after the video. 

Eventually, though, Kelly's dad moved on and ultimately married his new partner. 

"My mum grew incredibly jealous. She was upset and angry and told my dad that if he introduced us to her without my mum's permission that she wouldn't let him see us again."

So when the time came for Kelly to meet her step-mum, she was terrified that she'd never see her dad again. 

"Looking back, it's clear that my first initial thoughts were very much warped by my mum's own emotions. And also being a 10-year-old girl, the only step-mum I knew of was Cinderella's."

"I was angry and upset, and it felt like everything that could have gone wrong in my 12-year-old life was going wrong. Looking back now, they weren't my own emotions, they were a manifestation of my mother's anger, sadness, and resentment."

After a few years, Kelly began living week on/week off with her dad and step-mum. 

"It took getting used to, for a lot of reasons. But my step-mum was signing up to help look after and raise five kids that were not her own."

At first, Kelly was stubborn and tried to prevent her step-mum from playing a mother role, but over time, things changed. 

"After a couple of years and especially in my more formative years, like 14 through to 16 years old, she settled well into a mother role and taught me a lot about life, myself, and the world.

"I'd come home from school, work or a social gathering, and she was the first person I'd tell everything to. We sit out on the back deck and debrief about everything: work issues, friendship dramas, and just general queries about life. 

"She'll give me great advice and although sometimes I don't want to hear it and don't want to be wrong, she always seems to know what to say."

Kelly now considers her step-mum both a mother figure and a best friend. 

"I don't think people realise how significantly step-parents impact the children they inherit. It will never cease to amaze me how my step-mum signed up to look after someone else's kids and stuck around through the good, the bad, and the really bad, and is still here 12 years later. 

"I think of how different everything in my life would be if my step-mum hadn't been so good to me. I have learnt so much from her and I am so lucky she has stuck around through all the growing pains of learning to love all the parts of my family."

But the power of step-parents can work in reverse too, particularly when the step-parent either doesn't realise the power they wield, or worse, uses it to their advantage. 

When Mia's mum passed away, she was sent to live with her father and his wife. 

"Life did a complete 180," says Mia. "We were cut off from nearly everyone in our old lives, except for our schoolmates.

"My weeks had been packed with horse riding, piano lessons, and swimming lessons. But all of that came to an abrupt halt when we moved in with Dad and the step-family."

The worst thing, though, was the blatant favouritism.

"Her kids had the freedom to come and go as they pleased—all of them had driving licenses. Meanwhile, I was restricted to one outing per week, and anything beyond that was deemed 'too much'.  

"Occasionally, she'd take me out with her, or we'd go out as a family or attend an event, but those moments were few and far between."

The truth was, Mia felt as though her step-mother simply didn't like her. And it hurt.  

"One of her daughters once mentioned to me, 'I don't know why my mother hates you so much'."

But Mia still felt an attachment and a sense of loyalty to her step-mother – which made her apparent dislike of Mia all the more hurtful. 

"My high school friends were often confused by how I spoke about her. On the one hand, I'd complain about how she treated me. On the other, I'd try to understand her, rationalising her behaviour. 

"Despite everything, she was taking care of me. Maybe that's what made it so confusing—and, looking back, I wonder if it was a mild form of Stockholm Syndrome."

Mia was often told point blank that she was a burden, and she felt it too. Mia recalls one occasion where the words stung so much, Mia didn't know if she'd ever get over it. 

"She called me a 'silent killer' and said I must have caused my mum so much stress that it led to her death. 

"Imagine a grown adult saying that to a teenage girl, during an already confusing time, piling grief on top of everything – and never once apologising for it."

Eventually, Mia moved to Melbourne to study, but when the time came for her to return home, she realised she couldn't do it. 

"I left letters for my dad, step-mum, step-sister, and brother and blocked them on everything. I changed my phone number as soon as I could and cut off all ties with them."

Breaking away from her step-mother showed Mia that she could survive anything, but it also proved just how powerful a role step-parent plays in their children's lives — the power to make or break.

"I see my friends with blended families, and we often talk about it. I know it's challenging, but I truly admire how much care and consideration they put into the children involved, whether biological or not."

*Name changed for privacy reasons.

Feature image: Getty.