She left her husband and ran off with some young 'stud'.
retired racehorses being used as 'studs'
a horse that has been 'put out to stud'
(..) His dreams... His desires... His most intimate of intimates. And from what l'm looking at, intimate is the stud muffin's middle name. Tell me, you're nervous in the service? Uh... not really. Freeze those knees! Korben is in the place and he's on the case! (..)1997 The Fifth Element