I'm not just relying on my memories from my own crim law class in law school; I pulled out one of my old textbooks to check myself in writing the comment. "Under common law, an intentional homicide committed in 'sudden heat of passion' as the result of 'adequate provocation' mitigates the offense to voluntary manslaughter." Joshua Dressler, Understanding Criminal Law (1995). The book goes on to discuss the specific case of the murderous husband.

I believe my account is accurate with respect to the common law, although possibly not with respect to the current state of the law in all common law jurisdictions. Hence the caveats about the law possibly having been changed by statute or otherwise.