Travis Barker at the heart of Kim and Kourtney Kardashian's feud?

The longstanding feud between Kourtney Kardashian and Kim Kardashian appears intensified, with insiders pointing to Kourtney's husband Travis Barker as a factor. 

While the sisters used to share a close bond, they've come to angry blows in recent years on their reality shows.

Sources on the Deux Moi podcast say Travis has been dealing with private issues that have caused Kourtney to isolate herself from the family more. This distancing is reportedly a cause of tension between Kourtney and Kim, who doesn't approve of how her sister is "handling things."

"The conflict is real, it’s not just for the show. Things have been s***y between Kim and Kourtney for a while.”

"Travis is going through some things right now that he is keeping private between him and Kourtney," they continued. "This keeps them more isolated from the family and is part of the cause of the rift between Kourtney and Kim."

The feud now involves the sisters' children as well. According to the podcast, the cousins are a "big part" of the growing rift between their famous mothers.

Read more: Kardashians cancel Christmas card tradition, fans think THIS is the reason

Kourtney's marriage to Travis, who has tattoo tributes to her all over his body, has brought major change to her lifestyle and priorities. Once a regular on KUWTK, Kourtney now keeps much of her personal life private with her Blink-182 drummer husband and children.

Her separation from the famous family unit coincides with the worsening fights with Kim. And their Christmas card tradition, a longtime staple of Kardashian fans, was abandoned this year amid the dysfunctional family drama.