In Sweeney Todd....?

Question

Why does Mrs. Lovett refer to Sweeney as Mr. Todd or Mr. T? And why is Mrs. Lovett called Mrs. Lovett? Once they get married, shouldn't they at least be able to call each other by their first names?

Answer 1

Mrs. Lovett wasn't married to Sweeney Todd. Her husband died. She was friends with Todd's wife and was jealous of her or something. Mr. Todd and Mr. T could just be nicknames.  

Answer 2

they were not married

Answer 3

I actually think it's a pet name she has for him,she is in love with him anyway. Plus,it fits with the lyrics :D

They never do get married,if you saw the movie version,it was just part of her dream sequence.

She's Mrs.Lovett because she WAS married,but her husband died.