Before they met, Amanda Prowse and her husband, Simeon, were single parents whose sons were best friends. After taking things slowly, the couple felt ready to tell Josh and Ben about their relationship – but they’d already guessed

When I first met Ben, I had no idea he was my future stepson. He was simply my son Josh’s friend from school and, just like meeting any of Josh’s friends, I made some offhand observations: a) I quite liked him and b) if he didn’t learn to eat something other than pasta he would struggle at dinner time in our house. I didn’t love him immediately or feel any special attachment. I had to learn to love him. But let me rewind.

By the age of 39, I had a failed marriage behind me, and I was juggling being a single mother of an eight-year-old boy while I managed a demanding career. I had worked hard at being in love in my teens and 20s, but now I could barely find time to drop Josh at the bus stop each morning, let alone make the time to start a relationship. In any case, our life was on an even keel. Except for the odd moment in the middle of the night when loneliness would strike, I didn’t feel we needed anyone else in our happy little family.

Until, one rainy Saturday nearly a decade ago, a big fat arrow fired by Cupid at close range hit me unexpectedly between the eyes. I had gone to watch Josh play rugby at school and, standing on the touchline wondering how much longer until the final whistle, I turned and saw a man approaching, smiling as if he knew me. He told me his name was Simeon and he was the father of Josh’s best friend, Ben. I stood beaming at him. I had never believed in love at first sight, but my heart felt like it was going to leap from my chest. I felt light-headed and dizzy, and I knew that he felt it too.

To begin with, we were determined to build our relationship slowly. After all, Ben and Josh were the most important people in our lives, and we needed to give them a chance to adjust to a change in the status quo. The boys were used to spending whole weekends together playing Pokémon, eating sweets and building forts, so our dates mainly consisted of pizza and a movie with the kids. Simeon and I still occasionally sneaked out to snog in car parks like nervous teenagers, but mainly we spent time ensuring the four of us could all be friends.

We planned to tell them that we were more than friends eventually, but life had its own ideas. One evening, driving up the motorway with two sleepy boys on the back seat, Josh suddenly piped up, “I think Simeon is your boyfriend!”

It was unexpected, but we had agreed to always be honest with the boys about everything. “Why do you think that?” I asked, playing for time, wondering if we had inadvertently slipped up and held hands. It turned out the clue was more innocuous, as Josh explained, “You let him swig from your bottle then you had a drink straight after and you didn’t even wipe the lid!” The cat was out of the bag.

Once the relationship was out in the open, we started spending more time with each other’s sons and our normal parenting rules went out of the window. The voyage into the choppy waters of parenthood is a scary one. I spent the first year or so wishing my son, Josh, had arrived with a manual. Thankfully, nature gave me a helping hand in the form of unconditional love. I held my newborn son and knew that he owned my heart.

But it is quite a different story when you welcome into your home a child who has been on the planet for nine years without you in their life.

I was so desperate to be liked by Ben that the rules and boundaries I set for Josh did not apply. “No, of course you don’t have to try the broccoli!” “Yes, you can play with the Wii just before bed time!” Simeon, likewise, found it hard to reprimand Josh, wanting to be seen as the goody and terrified of upsetting me.

When we eventually got married and started living in one house, it felt like I was in a constant interview for the role of perfect parent. As a result, Simeon and I were uptight, anxious and exhausted. Eventually, when Josh asked me, “How come you don’t tell Ben off for eating with his mouth open but if I do it, you go nuts?” we decided things had to change.

Continuing our policy of complete honesty, we explained that we couldn’t compromise our standards and behaviour any more to keep the boys happy but that we were nervous of getting things wrong as it was so important to us. We asked if they had any questions and Ben blurted out, “I’m worried Dad will love you more than he loves me.”

It was a heartbreaking admission from a little boy who had experienced upheaval.

“Oh, mate, that could never happen. You are his son! His baby! And you always will be.”

Then Josh asked, “Who do you love most, Mum?”

“You!” I replied, without hesitation.

We told each boy that while there was an infinite amount of love to go around, Simeon would always love Ben in a way he wouldn’t love Josh and the same was true in reverse for me. So are we bonkers? Possibly. Does acknowledging the truth make people uncomfortable? Sometimes. But the fact is, it gave each little boy the feeling of security. They knew that while this strange domestic merger was going on, their position was unchanged. They also knew that it was OK to rely on moments alone with their “natural” parent to talk through anything that was worrying them.

The transition into our blended family has been fun, educational, stressful, tough and rewarding. I still remember a day when Ben, aged 14, was asked if he needed a lift home from school. I was parked nearby with the window open and heard him say, “No, it’s OK, my mum’s here!”

It was the first time he had referred to me as his mum, and it is a moment I will never forget.

The boys are now 17 and no longer my little ones. They hate or love each other depending on the day of the week just like normal brothers. It no longer feels like two teams trying to get along, and over the years the boys don’t seek out their “natural parent” for advice or a chat – either one of us will do.

So do we have the perfect family? No. Have we made mistakes? Certainly. I’m sure the boys have felt misunderstood, ignored or singled out at different times. But both are happy and confident. I no longer think of having a stepson and a son, I simply have two boys of the same age who both drive me crazy or make me swell with joy. Yes I love them differently, and so does their dad. But, surely, as long as that love is deep and unshakeable, it doesn’t really matter in what shape it comes.

Will You Remember Me? by Amanda Prowse• is published by Head of Zeus, £10