(Spoilers Main) What if a husband offed his wife?

So, we all know that in Westeros, kinslaying is probably the most heinous, taboo, wretched crimes that anyone can commit, right (which makes me wonder why the fandom thinks that Randyll Tarly would've faced no consequences if he killed Sam and it became public knowledge)? A crime punishable by death.

Well, let's say a nobleman murdered his wife, and it became public knowledge that he did. What would happen to him? Would the king (or his liege lord depending on whether or not he's a vassal) punish him for such a deed? Would the family of the wife seek retribution How would this be handled?