It appears same sex couples in Korea can now get the same national health insurance coverage as heterosexual couples:
An appellate court on Tuesday ruled in favor of a same-sex couple demanding the same spousal coverage from the state health insurance program as heterosexual couples.
The Seoul High Court delivered the landmark ruling, overturning a lower court’s decision that marriage in South Korea is considered a union between a man and a woman, and there are no legal grounds to expand the concept to same-sex couples.
The appeals court did not give a specific reason for its decision.
Yonhap
You can read more at the link, but the big difference between spousal and individual health coverage in Korea comes down to the premium. Same sex couples had to previously each pay individual premiums while heterosexual couples were paying the married premium which was cheaper.