My step-sister Debbie and I have always been close and growing up, she knew all my secrets.
If a guy dumped me, she'd be there picking up the pieces and would always know what to say and do to make me feel better.
Even after I'd moved out of home we were inseparable and would catch up for lunch every second Sunday.
One day she confided that things between her and her husband were a mess.
I was devastated for her but their troubles had gone on for a few years, and they'd just grown apart.
They eventually separated and, this time, it was me helping to pick up the pieces and bring a smile back to her face.
Time passed and we got even closer as we both remained single and unlucky in love.
As all my friends got married and started having families, I began to feel more and more alone.
I longed for a child but whenever I started dating someone it always ended the moment I brought up marriage and children.
One Sunday when I met up with Debbie for lunch I could tell there was something different about her.
"What's going on?" I asked. "You haven't stopped grinning!"
"I didn't want to say anything because it's still early days, but I've met someone," she confessed smiling.
A couple of weeks later I was invited over for dinner to meet her new guy.
"Hi, I'm Greg," he said shaking my hand.
Tall and handsome, Greg had strawberry blond hair and bright blue eyes that crinkled at the edges when he smiled.
"Nice to meet you," I replied blushing.
Instantly I could see why Debbie was smitten.
Greg told the most hilarious stories and had us in fits of giggles all night.
Unfortunately, things didn't work out between them and they split up a few months later.
She didn't seem devastated, which would have been my main worry so secretly I was more disappointed that I wouldn't be seeing him around anymore.
One day while grabbing an afternoon coffee at the local cafe, I heard a familiar voice behind me, "May, is that you?"
Spinning around, I beamed as I realised it was Greg.
We chatted at the café for the next 20 minutes before he asked me if I fancied a drink. I agreed.
Minutes turned into hours, we kept exchanging long looks and forgetting to talk, and before I could even register what was happening, we were in bed together.
Afterwards, I was mortified. How could we have let this happen?
We swore to one another that it was just a one-time thing and we would never, ever confess to my sister.
When I felt nauseous a few weeks later, however, I suddenly remembered my night with Greg.
A home pregnancy test confirmed my worst fears.
While I was devastated about my betrayal, I was so excited to finally become a mum.
I knew I could never reveal who the father was to Debbie so I made up some story about a one night stand – it was the first time I'd told a real lie to her.
Then, the worst happened.
"Greg and I are back together," she said one day, about six weeks later.
"That's great," I lied.
When I finally had to face Greg again one afternoon at her place, I was terrified. And all day I caught him stealing sideways glances at my pregnant belly.
It feels awful keeping this secret from Debbie, but the truth would destroy her.
I need her support more than ever so for the meantime at least, I'm saying nothing.