I don't think it's a matter of can't, it's a matter of prosecutors can't force a spouse to testify. I don't understand why they don't go five miles off shore and do their underhanded business in international waters.
Dennis the Menace
Dennis has regaled us and his parents with disgusting stories about frogs, mud, bodily functions, and I want to say Ruff eating his own turds but talking about Margaret is where Dennis draws the line. You clean out your mouth, Mom and make sure I never hear those vile words come out of your mouth again.