From what that one guy said it only work if the voice actor recorded the dialogue, which I guess he didn't. So I am SOL. I'll just have to obsess in private over him I guess.
Just use your imagination.
It's not like any of the vanilla marriage NPCs say anything special.
They just get like 3 new lines...
"Where we gonna squat?"
"Here, eat this [censored]."
And they tack "Love" and "Dear" to the end of their greetings.