The Golden Honeymoon (1980)

Charley Tate, a nice enough guy but somewhat of a braggart, takes his wife Lucy on a trip to Florida for their 50th wedding anniversary. While there, they run into one of Lucy's old boyfriends. Even though the ex-lover is himself married, Charley feels the need to prove to his wife--and himself--that she made the right choice 50 years before.