Once upon a time, there was a newly married guy and gal.
They slept soundly, they slept late, they slept when they wanted to. Degrees of clothing varied.
Due to the aforementioned, soon they welcomed a baby boy.
The not so newly married
guy and gal had a dramatic change in sleep.
They slept intermittently, they slept much shorter, they slept when baby boy let them.
At five months, baby boy decided he disliked sleep, so he joined the guy and gal in their bed.
Sleep slowly but surely returned.
The guy and gal could not figure out how to get baby boy out of their bed.
Soon toddler boy was overtaking said bed, but again the guy and gal couldn't not figure out how to remedy.
And then, another baby boy was welcomed.
Toddler boy adjusted to his crib, while the guy and gal again acclimated to sleeping intermittently, much shorter,and when baby boy let them.
As history has a way of repeating itself, before they knew what was coming baby boy decided he also disliked sleep, so he joined the guy and gal in their bed.
but . . .
Unlike toddler boy, the guy and gal have successfully figured out how to get toddler boy to sleep in his crib [at least half the night].
And there was much rejoicing.
There is no crying. He just goes down awake and falls asleep. It is amazing.