A beautiful wife, or thoroughbred, who is broken or has issues. Like a rescue purebred you cannot otherwise afford or deserve once purchased you realise he/she has had a traumatic life and will require extra attention and care for the life of the marriage.
You are an average looking guy with and average income but have somehow landed a knockout. She is probably a rescue wife with history.
When you marry a woman from a poor country and bring her back to your rich country, such as the United States, thereby rescuing her from poverty and oppression.
She: I'm going to adopt a rescue cat
He: I'm going to marry a rescue wife