They just began to do it.
That's all.
Of course, anybody can see why: _now_ each one is calling me the other one's name along with their own.

That is, Mother is calling me Mary along with her pet Marie, and Father is calling me Marie along with his pet Mary.
Funny, isn't it?
But one thing is sure, anyway.

How about this being a love story _now_?
Oh, I'm so excited!.