Unless I'm REALLY forgetting something.... I think the Fiance thing was a white lie to try and dissuade the Princess from pushing the Marriage topic..... But suggesting that he is open to having multiple wives will likely backfire.
@Moraza Nah, you remember right. That's why Schnee is stepping in now - they're aware of the risks. "If you want to marry Shin, you need my approval" is the basis of the catfight going down here.
@Gilith They aren't - go back and read the earlier chapters (around 35-40 ish, I think). It's a ruse to keep assorted political bullshit away from Shin.
@Gilith I need to reread this it seems. Sounds a bit like a cover story since he expresses a bit of surprise that the princess bought it so easy. On the other hand, forgetting to include the beginning of the engagement as a cover or for real is a huge oversight. It has the feel of something that was included in the LN at some point but was forgotten in the manga.
@Moraza Well, from his point of view a person with an actual harem sort of situation going on is probably just unfaithful. It should be a turn off to someone to see it. What he did wrong here is thinking like a Japanese person rather than someone from this world's upper echelons who is probably at best going to end up in a political marriage anyway.