Tori Spelling "will never trust" husband Dean McDermott again, an insider said, noting that the couple's sex life struggles -- despite Tori's best efforts to keep things spicy in the bedroom -- are at the crux of issues plaguing them.

McDermott, 47, "has always been keen on having a very active and imaginative sex life," a friend of the couple told People magazine, adding that Tori has "always made their sex life one of her top priorities."

The problem, a