I was never a broody person, didn't want kids. At 32 something strange and chemical happened in my brain and I became very broody - stroking baby clothes in shops during my lunch break and crying type of broody! DD was born when I was 33. I had HG, we were lucky to both survive the delivery, then I had PTSD and PND. It was horrific. Having a small baby was the worst time of my life, it was soul destroying. It could have easily destroyed my marriage if my DH wasn't such a determined type.
We both knew we only wanted one. I think even if we'd had a smooth ride we'd still only have wanted one because parenting is relentless and the baby stage was not exactly a delight!
All baby stuff / equipment went to the charity shop as soon as it was outgrown. I never mourned the passing of the baby or toddler stage like some people do, I never mourned that she was growing up too quickly. I celebrated and felt excited by developments, love seeing the person she's growing up to be - never once looked back.
Folk who want more kids sometimes say they fell like someone is missing, they don't feel fulfilled or complete. We've never felt any of that - feel happy and complete as a family of 3, not wistful or thinking of what might have been etc. DD is 8 now and is the pride and joy of our lives, she;s everything we wished for and more.
But, we would never, ever want or have another. It's great with one - easy, fun, money not an issue. We can pretty much do what we like, when we like. There's no spreading ourselves thin, balancing funds, activities, time etc between kids - we wouldn't enjoy that.
It must be horribly painful to want more and live with an unfulfilled yearning if it's not possible, or to feel like you need to keep going til you reach x number of kids if circumstances make it impossible.