A man who
isn't the father of the child proposes to a pregnant woman in order to preserve her honour in a society with strong views on extramarital sex. Whether this is a suitable basis for a
happy marriage largely depends on the work's
idealism.
If it happens nowadays, the guy either has a
very strict
sense of duty or is just in love with the woman and making excuses. Also, expect his actions
to be criticised for implying that a single mother
can't raise a baby alone.
Sister Trope to
Shotgun Wedding.
Examples:
- In Deadwood, Ellsworth to Alma Garret, as she's bearing the child of a guy who's only (lovelessly) wed for the similarly-honorable reason of dutifully marrying the widow of his dead brother.
- Strongly implied in, of all things, Lady And The Tramp. After Tramp spends the night alone with Lady, Jock and Trusty discuss proposing to her to protect her honor.