Kris Humphries and Kim Kardashian; Kris Jenner (inset)
Angela Weiss/Getty; inset: Amanda Edwards/Getty
When reality star Kim Kardashian
and her NBA beau Kris Humphries
began dating 6-months ago, they almost instantly knew this "was it," says Kim. But for Humphries, becoming part of the close-knit Kardashian clan was no easy task.
Thankfully for him, Kardashian's mother Kris Jenner, couldn't be happier to have him become part of the family
. "He is so amazing and sweet and after spending time with him I came to realize he was such an important part of the family," Jenner tells PEOPLE.
"He gets along with every single one of us, and that is not easy to do," she admits. "When you date one of us, you date all of us. We're all going out with Kris," she jokes.
It was his easy-going spirit that most put Jenner at ease. "I see that spirit in Bruce [Jenner] and that I saw in Kim's dad (the late Robert Kardashian). We have a lot of big personalities and he lets us be who we are."
And as for making Kardashian happy, he's got that covered. "I haven't seen her this peaceful and content and over the moon, ever!" she says. "That makes me happy. When you're kids are happy, you're happy."
And Humphries has learned to stand on his own in the family. "It's hard to let someone in to such a crazy, big, dynamic family and have someone hold their own," she explains. "Kris does. And he allows Kim to be who she is. She is such an amazing person with such a big heart and she's such a romantic and he's exactly the same way. They're cute together."
For exclusive personal photos from Kim's engagement party – and all the details of her emotional proposal – pick up the new issue of PEOPLE, on newsstands Friday