Kathy Hilton believes her sister Kyle Richards‘ split from Mauricio Umanskywas a long time coming … and she expressed her fiery opinion on national television, no less.

Paris Hilton‘s mom made her highly anticipated return to “The Real Housewives of Beverly Hills” for part 2 of the reunion on Wednesday — and she didn’t hold back when it came to weighing in on her sister’s marriage.

The veteran socialite speculated aloud that Kyle likely didn’t rush into her decision to separate from the real estate mogul. As Kathy put it … “[Kyle]’s not a compulsive person.”

With that in mind, Kathy thinks it’s unlikely that Kyle would end her 27-year marriage over a few rocky months. The Hilton matriarch suspects her sibling has been considering the split for at least a few years.

As for how Kyle and Mauricio are doing in the aftermath of their public breakup … Kathy made it clear that they’re all hunky dory, doing their own things — shouting out Mauricio’s stint on “Dancing With the Stars” as proof. That was her view when this was filmed anyway.

Kyle — who has denied rumors she’s dating gal pal Morgan Wade — has somewhat changed her tune in recent months … as she revealed in an Amazon Live stream last week that she and Mauricio are allowed to date other people.

Kyle and Mauricio’s split is set to play out on season 2 of “Buying Beverly Hills” … the family’s other reality show. We’ll be tuning in!