Tales of the Unexpected (1979)

S4E6 Shatterproof

Gerry Williams, a successful property mogul, finds himself in a troubled marriage with the stunning but discontented Ellen. Their relationship has taken a turn for the worse, and things spiral further when an assassin is contracted to eliminate Gerry. However, the hitman crosses a line by growing too close to his intended victim, complicating the mission in unexpected ways.