Nick Stahl -- Wife Ending Search for Missing Actor

Nick Stahl's wife has decided to end the search for the missing "Terminator 3" star ... after he disappeared from friends and family for the 2nd time in two months.

Stahl -- who was MIA for a couple of weeks in May -- vanished again last week after checking out of an L.A. rehab facility against the advice of his doctors.

TMZ spoke with Rose Stahl ... who tells us she will no longer actively search for her husband ... and unlike the incident in May, she has also decided she will NOT involve police.