User blog comment:Bilitis/Poll - Who is your favourite spouse?/@comment-28529499-20160530184220/@comment-1746153-20160606091726

As much as I like Serana, I don't see why marriage to her would matter. It's just a formality, and you already have a (relatively) meaningful relationship with her. I mean, if you manage to get the proposal dialog, she says that she cares about you a lot, but feels like a ceremony and a married life aren't for her (I believe it's another case of lampshading through her dialog though).