How much harder is the second one?

I have a beautiful a 1yr old son. I’ve always wanted to have three kids until I had him, and now I’m cutting my perfect number down to two. It’s just…much more work than we could have ever imagined. We of course love him dearly and I would take a bullet for the little guy in a heartbeat. But we’re both dead tired all the time.

So my question is, how much harder is the second one? I expect that the experience and knowledge from raising my son will soften the initial shock that comes with having your first kid. But at the same time, is it doubling the exhaustion?? Is it like herding kittens where it’s always chaos? My wife is on the fence between having one or two, but I definitely want two. I had siblings to grow up with and couldn’t imagine not having them to play with and lean on.

So, how much harder is it when number two is introduced into your world?? Any insight or info would be much appreciated.