What it takes.

Being a stay-at-home dad takes a lot more than loving your kids.
It takes loving to spend time, a lot of time with them.
All the fathers I know love their kids, very few however love to spend a lot of time with them. They spend an hour here, another hour there but they cannot wait for Mommy to come back home so they can get away, as far away as they can.
Others will call Mommy for help at the first smell of poop or will pretend to not smell it until Mommy gets home.
Let's face it, for most men, spending time with the kids means playing with them and call mommy as soon as the shit hits the fan (sometimes literally!!).
Being a stay at home Dad means being a Daddy, a chef (although Mac'n'cheese and PB&J sandwiches do not qualify as gourmet cuisine), a chauffeur, a housekeeper (laundry and house cleaning are not done overnight by some special elves). You are also a teacher, tutor and mentor. And do not forget the numerous diaper changes. That alone is enough to run most men out of town!
You do not have to entertain the kids every second of the day. Every minute does not have to be planned as almost not a day goes as planned anyway, but you need to have a good idea of what you will do throughout your day so it does not end in chaos. Most guys see stay-at-home dads as lazy couch potatoes, doing nothing all day but watch their kids entertain themselves and think anybody can do it. These are the ones who would not last a full day watching their kids and taking care of the house chores.
Yes, taking care of three little ones is hard work. It is a full time job for which you are not getting paid. The reward, however is priceless.