Nicky & David: Possessive Partners?

Nicky Hilton and her boyfriend David Katzenberg may be inseparable, but not necessarily by choice. Insiders say David,25, is very possessive of Nicky,24, and doesn't like her talking to anyone he doesn't know.

"Whenever a friend approaches, he steps in front and intervenes," a pal who was with the couple at the July 13 Lia Sophia Clambake at the Boost Mobile Cabana in Malibu tells OK!.  "Maybe he just really cares about her!"