"Really, only time will tell if Miley and Kaitlynn will last, but right now they are being a support for one another during a tough time and enjoying their time together," the source adds of the pair, who were spotted kissing in Italy and spending time together in L.A.
Meanwhile, the source says that Cyrus' relationship didn't work out because "Liam wanted a more conventional marriage and that truly was the crux of their breakup."
"The bottom line is that they are very different people. Miley is a little wild and believes that people should be open and fluid, and Liam is low-key and laid-back. Liam has been very good to Miley and he in no way should be blamed for ending their marriage," the source says. "Liam loves Miley and it made him feel sad and a bit insecure when she openly talked about her attraction to other people. In the end, he didn't know how to control the situation and she didn't want to be controlled."
"Another issue that made it very difficult was, because they are so different, their friends never seemed to fit together and that affected their social life together," the source adds, before revealing that Cyrus "does love him so much."
"I'm sure she'll miss him terribly," the source speculates. "They talked about wanting children and living their married life but she is just not ready."
Previously, a source told ET that Hemsworth is "heartbroken that [Cyrus] moved on so quickly and so publicly."
"Liam loves Miley and is crushed by all of this. But right now Miley doesn't want to answer to anyone," the source claimed. "She still feels the need to explore herself, her sexuality and her music. Miley has been working in the studio and wants to blow off steam."
As for Jenner, who was spotted at the same club as model Josie Canseco Wednesday night, a source previously told ET that Jenner "remains friends with Kaitlynn, Miley and Liam" following the kiss between Carter and Cyrus, adding that he recently spoke to all three of them separately.
"He still cares deeply for [Kaitlynn] and his friendships with [Miley and Liam]," the source said. "He wants everyone to be happy and live their best lives."
When it comes to Carter and Cyrus' romance, a source recently told ET that "no one thinks Miley and Kaitlynn are in a real relationship, they believe it's more fun on vacation."
"For Miley, she's having fun, and for Kaitlynn, it seems too coincidental that she is hooking up with a huge music star, when that's what she wants most for herself in life -- to be famous," the source said.
Watch the video below for more on Carter and Cyrus.