Old old movie. What I recall is this woman is in love with a man who of course goes off and returns married to someone else. There's a war or something going on and there's an outbreak of scarlet fever or cholera etc. The man in question becomes infected and those infected are being sent to an island. The wife cares more for herself than her husband and won't go with him. The other woman who's always been in love with him accompanies him to the island.

Jezebel