Kim Kardashian and Pete Davidson’s romance continues to grow more serious with each passing day. In fact, a source says he’s even met her four kids with Kanye West (North, 8, Saint, 6, Chicago, 3, and Psalm, 2). “Pete’s bonded with Kim’s entire family,” the source tells Us, noting that her sisters and mom are thrilled with how upbeat Kardashian, 41, is when she’s with the comedian, 28. “They seem like they’ve been together longer because of how comfortable they are with each other.” The duo, who just returned from a romantic getaway in the Bahamas, are facing a busy winter — Davidson will be filming Saturday Night Live and Kardashian is releasing new products — but they’re not worried. “Kim is so relaxed now,” shares the source. “She went…