Many, many helpful people tried to tell us about how much adding a baby to the family dynamic would change things, but nobody was really able to quantify it for my logical brain. What does it mean that things get "a lot more complicated?"
I will try to explain my view after 8 months for any of you other logical brain people.
Before Joshua arrived, I assumed that this "change" would be a matter of addition. The whole "1 + 1 = 3" thing. That sounds like funky math, and it is. The sum of the parts is much more (fun, complicated, messy, crazy, time consuming...) than you think going in. But still, that is only half of the story.
In reality, there is even more funky math involved. That would be a multiplier effect added in the mix, and there needs to be a variable on both sides of the equation.
Something weird like 3x(Y+H) = 3x(Y-W) where x is a wild card and H and W are the relative moods of Husband and Wife and Y is whatever else needs to be happening at a given moment. You math geeks can tear that apart if you want, because we are not dealing in real numbers here. And figure that the value of H and W change daily.
Basically, with a baby, any change in routine of one person has a drastic effect on the other person, causing complications, confusions, unexpected consequences and the occasional nasty look.
The key, of course is being flexible and communicating changes in routine ahead of time. And when that doesn't happen, make the baby laugh and everything gets better.
Life does indeed change a lot. And by a lot, it is in orders of multiplication, not addition.