Here's an interesting case for the social historians.
So one guy steals a couple hundred thousand dollars from a school district, and his gay partner (the former superintendent) steals a cool million. The supe cuts a plea bargain that says that he'll testify against others in the case (over $11 million is missing). The first guy says oh no, we're a couple and I want to assert spousal privilege. They have been partners for 33 years, and have been registered domestic partners since 2002.
Put simply, our system of law does not require spouses to testify against each other, or parents and children against each other. The confidentiality protected by these laws is similar to doctor-patient or attorney-client privilege.
So should a gay person have to testify against his partner? Ignore for a moment the fact that it was part of the supe's plea bargain. Among the rights of marriage that gays seek, should this legal spousal privilege be one of them?
I don't see how it can't be.