In the US, medical issues can bankrupt people, even if they have insurance. If the couple married, his wife's income would be fair game to the hospitals and insurance companies.

I know a distant relative in the Midwest who's wife had a stroke. After about a year they made the difficult decision to get divorced because the aftercare was ruining them financially (she couldn't live at home). By divorcing, she became eligible for federal assistance, allowing her husband to keep a house over their children's heads.

This is the reality of healthcare in the US.