The Twilight Zone - The Long Morrow

Commander Douglas Stansfield is selected to be the first astronaut to go on a deep space mission. He will be away for 40 years but for much of that, he will be in stasis and on his return he will hardly have aged. Stansfield is a seemingly ideal candidate as he is single and has no close family. Prior to his departure however, he meets the beautiful Sandra Horn and they fall very much in love. Forty years later, Stansfield returns but it seems he and Sandra had their own way of dealing with the 40 years since they last saw each other.