Connecticut's Supreme Court is being asked to decide whether there are legal limits to the confidentiality of a conversation between a married couple.
The court heard arguments Wednesday in the appeal of Sheila Davalloo, who was convicted of murdering a rival for the affections of another man.
Anna-Lisa Raymundo was found beaten and stabbed nearly 20 times in her Stamford condominium in November 2002.
Prosecutors say Davalloo killed the 32-year-old Raymundo because she also had been in a sexual relationship with Raymundo's boyfriend, Nelson Sessler.
The three worked together at Stamford-based pharmaceutical company Purdue Pharma.
Davalloo's laywers argue the trial court should not have allowed her husband to testify about incriminating statements she made to him.