7th Heaven (1928)
A poor woman is rescued from a beating by a sewer worker. When the police want to take her away for being destitute, the two pretend to be married and then have to keep up the pretense until the authorities conduct a visit to confirm they're living together. But, by then, they've become contented roommates and have maybe even fallen in love.
That's cute and I wish the story had stopped there. But nope -- he has to go to war and get injured, she has to work in a munitions factory and fight off advances, then he has to come home after being reported dead, which is happy! But, dangit, he's blind now. It's too long by at least 30 minutes and has enough story for two movies.
C