There is absolutely no way of knowing how having children will affect your relationship. Having a rock solid partnership for a decade, sharing the same interests, household chores and outlook on life counts for nothing when you are sleep
deprived and the baby is actually there. You now have little to no time for interests, feel resentful of the chores you have to do while looking after a demanding baby/ being at work all day, and small and large decisions once they concern another human being who you are responsible for won’t automatically be unanimous, and therefore an added source for stress and potential disagreements. You cannot predict the parenting style of your partner once your baby appears and develops into a child, especially one they weren’t anticipating - personality, behaviour or health-wise. Nor can you predict how your partner will feel at the change in dynamics of your relationship, which would obviously be closer when it was just the two of you and neither had to share/compete for the other’s attention or affection.
When you have a child, rather than it necessarily bringing you closer (at least in the early years) it can be more a case of struggling to find and negotiating time to yourself - child and partner-free, as this is a rare commodity that ppl are aware of but cannot understand its impact until they experience it for themselves.
Many couples survive despite the challenges of the early stages and many don’t. For a lot of ppl, mainly women, it comes as a massive surprise and shock when their partner does not become the father they imagined or expected, and many men would argue that their partners changed unforeseeably once they became a mother. These are usually men who expect their lives to be more or less unaffected by parenthood, yet are surprised that their partners are too tired or pissed off for constant sex or to hear about the minutiae of their day when they take care of the majority of the childcare and household chores, and they both see each other in a different and more resentful light. Some men step up, some don’t. The difficult early years stage doesn’t last forever but the damage can if it’s not addressed. Also there are obviously other challenges beyond early years - finances, employment, health, teenagehood etc that are ongoing.
You cannot predict whether the strong team mentality of a childless couple will transfer to parenthood, it’s impossible to predict. Many women are completely blindsided by their partner having an affair when they believed they were happy, and the man blames it on stress, losing the partners attention, wanting to be seen as attractive etc - these were formerly ‘good’ men. It obv works both ways too and the woman can become more receptive to other ppl’s attention if she isn’t happy and feels resentment towards her partner for not pulling his weight, or just seeing her as a mother/nanny and not a desirable woman any more etc.
Parenthood definitely changes you - physically, mentally and emotionally if you’re a woman. The physical side is not focused on as much as it should be IMO. This can have a massive effect on women’s MH, how their partners see them and how they see themselves.
Believe it or not, I’m not trying to put you off, just make you aware that there is no guarantee either of you will be the same pol
you started off as, despite being together happily for 10 years. You know each other well but only as non-parents. Shit happens. So I guess you have to view it as whether you really, really want to be a parent - if you do above anything else and have a strong belief your relationship can go the distance - go for it, but be prepared that things MAY change significantly and your relationship won’t survive however long down the line (ie you may become a single or co-parent).
It is a massive decision that should never be made lightly and certainly should never be viewed and undertaken thinking that things will largely be the same throughout because they won’t, but that’s not to say it won’t work out for you.
Good luck with whatever decision you make!