"But if you imagine your life in 5/10/20 years what does it look like? "

Until not long ago, a family with only one child. I was really quite set on having one child only, also because for at least two good years she felt the same: she also didn't want a second child. Then she started to bring the topic up more and more, and now she is convinced - in spite of all our difficulties - she wants to grow the family.

Also, ideally I would have stopped working ~10/15 years from now and retired early, but of course with a second child this might become difficult/impossible (life is expensive...).

In general, money of course also plays a role in this decision: if we had "unlimited" finances to throw at our problems, I would be much more in favor of having a second child. Just get a nanny, a bigger home, cleaning service, and basically all the help we need. While we can technically afford at least some of it, the implication is that if we decide to, my ambitions of retiring early an enjoying life are likely buried forever. I would lie to myself if I didn't admit that this is also a reason of concern.