That is the starting point of this movie, which is not a normal romantic comedy just by the fact that from the beginning of the movie we are already aware of the end result, Maya, the eight years old girl who pronounces such words.
In the aftermath of this first school lesson, this girl decides that she would like to know why his dad is divorcing her mom (no really spoiling anything here as it is already in the movie description).
The father tries at the beginning to avoid the question and just states "it is complicated". Obviously, such a lame answer does not satisfies the curiosity of the girl or the spectator, therefore the father is "forced" to start telling her "the story", which starts on 1992.
In some way the movie remembers me of "how I met your mother", the TV Series. In both of them there is story from the past about how the parents of someone met. The main difference here is the length of the story, which is limited to the around two hours for the movies and three seasons from the TV series (so far...) and of course the same nature of the story.
Here we have the father who is explaining to his daughter which girls he was dating and when, but without saying the real names.
In this way, neither the daughter nor the spectator knows which one he married and therefore which one is, actually, the mother.
Along the movie three different women are presented as protagonists of the sentimental life of the father.
In an alphabetical order, they are: April, Emily and Summer.
Each one is, obviously, different, not only in their character, aspirations or behavior, but also in their physical appearance.
And all the three are or were involved in a sentimental way with the father, so for the girl, anyone of them could be her mother and she, along with the spectator "has" to guest which one is "the one". Of course, as spectator, you can just don't play along and not try to discover it, but in doing so you are going to miss a big part of the fun of the movie. Which, on the other hand, is full with good dialogues, very funny remarks from the little girl about the past life and habits of her dad and also some weird situations.
Again not a philosophical, huge ethical debates, moral questions movie, but just a movie to make you smile and maybe a little more happy.
And now, which one is your bet, April, Emily or Summer ?