it would depend on the social classes involved, I think.
A lot of the time, for Holders and the like, marriages are political things, and not romantic things. So, as long as people are discreet about their affairs, then while some people, such as the religious establishment, would frown, it'd be acceptable to an extent, amongst Holders.
And in that situation, divorce means dissolving a political arrangement, which would have repercussions. So would be frowned upon quite a bit more, by Holders. Less so by the religious establishment, because they know the marriage was a political one to begin with, so when someone asks for a divorce, the priest would tend to sigh and say "fine."
For commoners, it'll be different, I think, with affairs and divorces frowned upon a lot more.