Lots of war movies
Apocalypse Now
Full Metal Jacket
The Thin Red Line
The Longest Day
A Bridge Too Far
The Bridge on the River Kwai
Hell in the Pacific
There’s a romance between Maggie and Finn the pig farmer.
Nah, there’s a romance between Kane and the alien which is consummated and results in offspring. 
The Ladykillers.
Monty Python and the Holly Grail
Yellow Submarine
A Hard Day’s Night
n/m.
That’s right, now I remember. Okay, scratch that one.
Well, since many are being posted that are more recent than the 70s…
Moana.
I won’t grant Lawrence of Arabia. That always read to me like a rape.
You never know what would have happened. I doubt a woman whose husband was killed by (in part) Curtin’s decision would just up and marry him.
Daud and Farraj, then.
However, I did put the smilie there because the homosexual relationships in the film are never made explicit, in keeping with the time period.
They were married, and that early part of the relationship was shown. There are also hints that the feelings are there, but neither can be honest about it.
*Never Give a Sucker an Even Break
Nah, Anthony Quinn and Maria ride off together at the end.
2001: A Space Odyssey
Romeo & Juliet (it was more of an infatuation, really)
Remind me what you’re referring to here?
Stalag 17
20,000 Leagues Under the Sea
Animal and Betty Grable?
Respectfully, you are incorrect. They are not married at any point in the film.
They are lovers. It is debatable whether their relationship can be called “loving” because Barrymore’s character is a control freak/manipulative a-hole (and solipsist) who is not truly capable of loving another person. As such, I would argue that the Lombard character is not truly a love interest for him, only another person to be used for his own ends.
Cody, a fortune hunter, tries to horn in on the discovery by the trio. They decide to kill him, but he’s killed in a confrontation with the bandidos. They find a letter from his wife in his effects. At the end, Curtin goes to seek out his widow.