I've been asked more than once if it was harder to transition from 1 child to 2 children or 2 children to 3 children. (Incidentally no one has asked me if it's harder to go from 4 kids to 5, I guess they assume I'm crazy or insane.)
But I answer the same way every time:
One person (ME) to getting married was the toughest transition. Additional children don't even come close.
Trust me that this doesn't say anything about my wife. (I'm the problem here, I promise.)
But moving from just thinking about one person (ME!!) to also thinking about someone else (ANYONE ELSE!) was the biggest transition. Now that I've made that leap, it's not nearly as hard to add an additional person (or 5) to the mix.
One of these days I'll stop being self-centered... it just might take awhile!