'I was born outside of my dad's marriage. I'm still bearing the scars.'

For the best part of three decades, music legend Dave Grohl has been amassing an adoring fan base thanks to his down-to-earth vibe, kindness and humility. Despite a pedigree that includes two of, undoubtedly, the biggest bands in history, he's managed to do it all with the energy of rock 'n' roll's most beloved golden retriever.

Until now. Yesterday, the 55-year-old Foo Fighters frontman made a public announcement that saw his house of cards come crumbling down.

"I've recently become the father of a new baby daughter, born outside of my marriage," he wrote in the post. "I plan to be a loving and supportive parent to her.

"I love my wife and my children, and I am doing everything I can to regain their trust and earn their forgiveness."

He added: "We're grateful for your consideration toward all the children involved, as we move forward together. Dave."

The confessional post was the first thing I saw when I woke up, and like so many others it left me a little rattled.

My initial: "No! Not Dave Grohl! This must be a joke, he's a family man" reaction soon settled into an uneasy ick as I digested the casual tone with which this huge admission had been delivered.

I'm not a Dave Grohl superfan by any means. I tried to read his biography and failed, but I've always liked his persona in interviews and, as a Gen X'er, Nirvana songs still give me a visceral reaction tied to teen angst, I suppose. However, this confession felt nothing like the man who was just as enthused to talk about his wife and kids in interviews as he was when he was talking about music.

He gave the news of an infidelity that is bound to be earth-shattering for so many people he loves with the same energy as a 'taking a break from social media for a minute, see you guys when I'm back online soon' announcement.

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No big deal. Just an affair. Just an affair that made a human being. Just an affair that made a human being that wasn't with my wife.

As someone who was born 'outside' of my father's marriage, I'm sad for this "new baby daughter" and the scars that she may bear through no fault of her own.

Like Dave Grohl, my dad was a very married man and a father when he met my mum. Also like Dave Grohl, my dad welcomed a new baby girl outside of his marriage.

Unlike Dave Grohl my dad didn't try and work it out with his wife, jumping ship and making a new life with my mum which lasted nearly 50 years until he passed away a few years ago.

To the outside world, we would have looked like a regular family: working dad, working mum and a little family consisting of myself and a younger sister who came along a few years later.

While their relationship might have lasted decades, it was fractious, and it wasn't until I became an adult working through my own 'stuff' that it became more and more apparent that the way their relationship began – the way my life began – was a main reason for the cracks.

While she never would have, and probably never will, voice aloud the insecurities that stem from a relationship born from an affair, it's obvious to me now that my mum had major worries about it.

My dad adored my mum, he worshipped her. It was almost obsessive. She was 15 years his junior and a far cry from the suburban, Stepford wife-like mannerisms of his first wife. My mum never nagged, never begged, she was cool and chill. He pursued his hobbies with vigour and anything he wanted, he got.

His friends were jealous: "You're so lucky!"

And he was.

Her? No-so-much.

She was introduced to my dad by mutual friends in the mid-70s. My free-spirited mum was sunbathing, topless, in the backyard. My country-raised, good-boy, dad never stood a chance.

I was an accidental pregnancy from a one-night stand. Mum went through the pregnancy alone, and when I was just days old she turned up at his workplace shoving me into his arms, asking: "Are you in or out?"

He was in.

Dad was unlike any of the men my mum had been involved with before. He had a good job and they could make a life together, the kind of life that she could only have dreamed of before.

But it's obvious to me, now, that she was never settled in that life. She cultivated the persona of an independent woman who didn't really need anyone or anything. I think that was part of the reason my dad adored her so much. But her actions and the way she catered to my dad's every whim tell the story of a woman who would do anything to keep her man.

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It was a rollercoaster of her simultaneously pushing him away with her aloofness and holding him near with the dependence he had on her for every single aspect of his life.

Quietly, her life became all about making his life easy. Laundry: done. House: spick and span. Lunch: made and in the fridge. Life admin: taken care of. Dinner: on the table.

Dance recitals, school assemblies, parent-teacher interviews, sports pickups, playdates, school notes, nits: for all the mundane 'chores' of parenthood he was off the hook. It was always my mum carrying the load.

Before it had a name, this was 'pick-me energy' all day long. And all of this was undertaken while she maintained her cool, boho 'whatever man' attitude to their relationship.

And, let me tell you, that model has shaped every encounter I have had with men my entire life.

Outwardly I am not a jealous person. Like my mum, in my marriage, I am cool AF.

You're going to a party with strippers? Have fun. You want to play in a band with groupies? Have at it.

After a boy's weekend, my husband will tell me everything and we laugh together like I'm one of the boys. He doesn't sugarcoat anything because he knows I am not going to flip my lid.

But it's a fake confidence. A mask. I'm going for that gold star of wifedom, just like my mum.

My husband's life, through no doing of his, is just like my dad's. Laundry: done. House: spick and span. Lunch: made and in the fridge. Life admin: taken care of. Dinner: on the table.

It's been like that in every relationship I have ever had. But when you make such a big show about not being needy, your needs don't get met.

I've always had a hard time trusting that people genuinely like me, and I find myself morphing into what I think they want me to be, always expecting that I'll be found out and they'll leave me. Quite often I'll push people away before that can happen.

Part of this stems from the way my mum modelled that very same behaviour and even more of it stems from the fact that I am a child 'born outside' of my dad's marriage.

My dad left his first family and never looked back.

Two of my older siblings were already adults living their own lives when my dad met my mum. Over the years my younger sister and I met them once or twice, but the energy was clearly charged and none of the adults involved ever actively pursued cultivating a close sibling bond between us.

That leaves three half-siblings I have never met. Hopeful attempts at making a connection with them over the years have been met with hostility.

We are the 'others'. The naughty ones, the dirty ones, the ones born out of wedlock, the ones who came from debauchery and secrets.

I feel particularly stained. I'm the one who came along and caused the split in their family.

My mum is the temptress, the 'other woman' My dad is the adulterer, the philanderer, the wolf. I am the imposter, the mistake, and the one who changed it all.

Sure Dave Grohl may be remorseful and confident that he can prove himself to his family while becoming a great dad to this new baby girl, I hope it all works out. But the off-hand 'nothing to see here' tone of his almost casual announcement bears no tether to the reality that is coming to his family.

Particularly to the new baby girl 'born outside' of his marriage.

The author of this story is known to Mamamia but remained anonymous for privacy purposes.

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Feature image: Getty.