"John and Olivia are exhausted a lot of the time and aren't getting much shut-eye," the source confides of the pair, whose first days as Mom and Dad included nervously checking in on their newborn while he slept soundly. "They're new at this and had to learn on the fly."
Despite entering uncharted territory, Mulaney, 39, and Munn, 41, have already nailed down a routine when it comes to feedings, nap time and diaper duty.
The comedian (who claimed in 2019 he didn't want kids) has also quickly warmed to fatherhood. "He's been very hands-on," shares the source, "and helping out with everything."
Though they're now a family of three, Mulaney and Munn are making sure not to neglect their own relationship. The couple who began dating in early 2021 after the stand-up star completed a stint in rehab — and filed for divorce from artist Anna Marie Tendler — are "loving this time together," says the source. "It's a chance for a fresh start."
An insider previously told OK! the duo's romance had hit a few snags due to Mulaney's reluctance to commit. "They just aren't in sync," the insider said in October. But the birth of their boy has ushered in a new chapter.
"They're closer than ever," spills the source, adding that they plan to spend their time nesting until Mulaney returns to work for his From Scratch tour in March.
Going forward, Mulaney and Munn are committed to making their long-distance romance work — not just for their baby, but themselves, too. "Their romance was a whirlwind," admits the source, "but they're in it for the long haul."
"They knew their lives would change," a source says of the two, "but they didn't know how [much] until they brought their baby home."