[WH: 31, What the Aelfinn Said, 588]:

"She is my wife," [Mat] said softly...
"What?" Egeanin squeaked, her head whipping toward him so fast that her tail of hair swung around to slap her face. He would not have thought she could squeak. "You cannot say that! You must not say that!"
"Why not?" he demanded. The Aelfinn always gave true answers. Always. "She is my wife. Your bloody Daughter of the Nine Moons is my wife!"

Egeanin doesn't say "What? WTF are you talking about?", she says, "You MUST not say that." So we wondered, post-WH, if there was some special significance to him saying that. Amy Gray suggested: "What if Seanchan marriage customs are such that all you have to do to be married is say it three times? If this is the case, they're already married! The more I think about it, the more I like the idea. I think this is my new pet loony theory."

Well, not quite, but damn close for a loony theory.

[COT: 28, A Cluster of Rosebuds, 625]:

Egeanin: "You can't think she'll complete the ceremony, can you? You can't be that big a fool."
Mat: "What ceremony? What are you talking about?"
"You named her your wife three times that night in Ebou Dar," she said slowly. "You really don't know? A woman says three times that a man is her husband, and he says three times she's his wife, and they're married. There are blessings involved, usually, but it's saying it in front of witnesses that makes it a marriage."

Heh.