Very curious. Had to read it twice to grasp the plot more and to make the names stick better. I found it more appealing after the second reading. It doesn't feel like a love triangle.. More like a square (?) since we have koizuka, the princess, the captain and the queen.
Quite disappointing how both the princess and koizuka was waiting for each other to confront one another about the marriage to the queen, but it seems like the princess is a tsun, so, for me it feels like it was koizuka who should've done the first move.