I know a lot of people, both men and women, who married and had kids young that have turned into party animals following a divorce, as though they're trying to make up for not experiencing that during their youth. The difference is Nick and Kayla doing that while they're still married and bringing it into their home while half of their kids are still young.
"Still married" means nothing. Many people live totally separate lives while remaining married, including establishing new relationships. Will and Jada Smith are "still married", ffs, despite having been separated for years.