Most couples wait around three years between saying 'I do' and having their firstborn.
Five months into their marriage, Meghan and Harry are expecting their first child.
I get it: Meghan's 37 and any woman who has ever toyed with the idea of having children has been traumatised by seeing those fertility charts with the alarmingly abrupt decline post-35.
The pressure is on all older women, who meet partners later in life, to get on with it or face the rollercoaster that is IVF.
Like everyone else, I'm thrilled Meghan got pregnant (what appears to be) effortlessly — but, at the same time, I also think it's kind of a shame that it happened so fast.
These two are smack bang in the infatuation period and still really getting to know each other.
In the two and a quarter years that they've been together, they've already dealt with so much.
They had a period of highly secret dating (when they basically stayed inside), announced their relationship to the world (which provoked some pretty disgusting trolling and major family dramas on her side), planned a royal wedding and got married, watched with microscopic obsession by the world.
That's a lot of stuff to juggle, on top of building a healthy relationship.
Most other couples spend that time getting to know each other, meeting each other's friends and families, s****ing themselves stupid and having some adventures.
Yes, I know, Meghan having a baby is a lot different than the rest of us having one.
Even if she doesn't choose to use it, there will be an army of nannies and hired help at the ready, to help her through. The royal couple will no doubt be protected from the sleepless nights and relentless mundane chores of parenting most parents endure.
But having children very early into a marriage still means less time for two and will still have an impact on their relationship — there's no escaping it.
Here's the issues any couple struggle with when they have children soon after meeting.
The 'just us', childfree stage is important in relationships because it sets the foundation for a long-term marriage.
The more 'happy history' you build and the higher percentage of good times you have in the marital bank, the better your relationship will hold up when it hits stressful periods.
Lots of therapists call this 'child-proofing' your relationship.
Most parents say having children is the best thing that ever happened to them. What they don't tell you is that it's NOT the best thing to happen to their marriage.
Ninety per cent of married couples report their relationship satisfaction declines once they have their first baby, according to an eight year study from the US.
The better your relationship foundation, the better you're able to deal with it.
Even with piles, swollen ankles, morning sickness and feeling 'fat', lots of couples still find pregnancy exciting and romantic.
If you've done your fair share of partying, a night in with Netflix and a small baby does seem far more appealing than yet another club opening.
Batten down the hatches though: looking in at the newly-painted nursery, holding hands and wistfully imagining the baby sleeping in the cot is one thing.
The reality of a screaming baby in there, is quite another scenario.
Pregnancy is tiring but the years after your first child is born is when there's the most strain on marriages.
The first two years after the baby is born are the 'shock years': if someone tells you their marriage hasn't changed, they're simply not being honest.
Jancee Dunn, the author of How not to Hate your Husband After Having Kids, says she knows couples who hardly spoke for two years after their baby was born.
Even worse, a lot of mothers are terrified to tell the truth about how hard parenting is, for fear of being seen as a 'bad mother'.
Dunn says she and her husband Tom fought daily but didn't confide in anyone "because in the stagecrafted world of social media, every beaming parent with a newborn is #SoBlessed".
Most people believe parenting is going to be the most rewarding part of life, but research tells us it's quite the opposite.
Matthew Johnson, Professor of Psychology and Director of the Marriage and Family Studies Laboratory in the US, surveyed 30 years of studies on the psychological effects of having children and came up with some dismal conclusions.
Having children causes profound changes in a woman's happiness and marriage — and not for the better.
On average, any couple's satisfaction with their relationship falls during the first years of marriage.
Comparing childless couples with couples who have children, the rate of decline in relationship satisfaction is twice as steep for those with children.
(Ironically, as your marriage becomes more miserable, your chance of divorce gets less: people do stay together 'for the sake of the children', even if it's unhappily.)
Young couples having a child for the first time are especially likely to have 'rose-tinted' expectations and think having a child will bring them closer together.
What really happens is your relationship moves from fun to functional: you become business-like in your dealings because your lives now revolve around negotiating a never-ending list of mundane but time-consuming things.
Feeding the baby, bathing the baby, getting the baby to sleep: that's a fraction of what's suddenly on your to-do list that replaces going out to dinner, having sex, meeting up with friends.
Is it any wonder the relationship changes dramatically?
The biggest predictor of overall life satisfaction is how happy we are with our spouse.
Parenting puts huge pressure on both of you: it's not just repetitive, boring tasks and sleep deprivation, realising this little person depends on you for their life, is utterly overwhelming.
If your partner steps up to the table to help shoulder both the chores and the emotional responsibilities, you end up loving them more.
But if their life doesn't change — he's still going for a run in the morning, having a drink at the pub after work, sleeping in on Saturdays — you won't just resent your partner, you can end up despising them.
Regardless of whether one of both parents work, full-time or part-time, it's Mum who is the one who's expected to change her plans to suit the children.
If you've been together for a while before having children, you've had time to plan and negotiate what this will look like: it's less of a shock when it happens.
We might think we're different to our parents and grandparents but when it comes right down to it, most parents revert to stereotypical roles once they have children.
What tends to happen is women work less after children to spend more time looking after them and men work more to take on the increased financial responsibility.
Time together is reduced — and you're both living in different worlds.
Dad's still out there, having conversations that don't revolve around the baby and living in the real world, up on current events and enjoying a social life.
Meanwhile, the new mother's world shrinks.
She's got no time or energy to do little else but look after the baby, making her feel isolated and insecure socially.
He walks in the door after work, you shove the baby at him, desperate for time alone to do everything you haven't been able to.
'Hi honey, how was your day?' is replaced by 'Here. You take her/him'.
Difficult even if you know each other inside out and have done for a decade; even worse if you realise you actually don't know your partner that well at all.
I've yet to meet a couple whose sex life didn't nosedive after the birth of a child.
Quite apart from exhaustion, the physical after-effects of giving birth, hormonal mood swings and redefining yourself from 'lover' to 'mother' mean sex slides to last priority status.
Sex doesn't even occur to you a few months after giving birth: it's something you did in another life and possibly won't ever do again.
If you're still in the early stages of your marriage with sex very much on the agenda, the drastic change from 'lots' to 'never' can be harder to deal with.
The really interesting thing about having babies and relationships, is, despite all the negatives — and as we've seen there are many — most mothers and fathers still rate parenting as the best thing they ever did.
"I knew I'd love the baby, but I didn't realise I'd be 'in love' with it. We are both utterly besotted. Exhausted and in shock but still besotted," said one friend of mine, six months into parenting her firstborn.
If you make it through those first two years, things ease up a little.
Yes, it is just a little (hello terrible two's) but enough for you both to see the light at the end of the tunnel.
The older your children get, the higher the level of relationship satisfaction grows.
The world is full of couples who met and got pregnant, accidentally or deliberately, within a heartbeat and are still very happy together, not regretting a thing.
As one friend of mine put it: "When is a good time to have a baby? If you wait for perfect conditions, you'd never do it."
The trick to emerging from parenting, strong and still together, is to go into it with realistic expectations of how hard bringing up children is going to be.
The less 'fairytale' the fantasy, the better the parenting experience is.
* Visit traceycox.com for more of Tracey's views on sex and relationships and to see her product range and books.
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