What's the Name of That Book??? discussion

I feel like this book has a name like "this is too secret" I remember it being about a girl and she's talking about a boy who goes to her school who has two names because his parents could never agree on anything and they eventually got divorced but chose to live together to raise him. The parents halve the house they live in so that there is a clear difference in decoration.

I'm pretty sure I read this book before 2014

It sounds a bit like The Problem with the Puddles by Kate Feiffer, except the child with the parents who disagree is a girl called Baby. (Mrs Puddle wanted to call her Emily and Mr Puddle wanted to call her Ferdinanda so the nurse at the hospital just wrote 'Baby' on the birth certificate - everyone calls her Baby apart from her parents, who call her by the names they wanted to use.) Not sure about the house being split in half but they have two dogs, because they couldn't agree which type of dog to get, etc.

The Name of This Book Is Secret

That's it! The name of this book is secret