Ethel Kennedy Stabbed In Back!

Sister-in-law gave Marilyn Monroe her BLESSING to cheat with Bobby.

ETHEL Kennedy, who for decades turned a blind eye to reports husband Robert Kennedy cheated on her with Marilyn Monroe, has been humiliated by her own sister-in-law — who confirmed the sizzling sexual affair!

A bombshell letter written by Bobby’s sister Jean Kennedy Smith to Marilyn in the early 1960s has surfaced — and shockingly reveals Ethel’s sister-in-law knew about the affair and approved!

“Understand that you and Bobby are the new item!” Jean, now 88, wrote. “We all think you should come with him when he comes back East!”

Kennedy insiders say the note has left frail Ethel, also 88, reeling.