With the new dialogue for wives and Serana not caving any time soon, I decided to get my character married. The only problem is that my Amulet of Mara seems to be broken, because no one has the "Interested in me, are you?" dialogue while I'm wearing it.

did you keep going with the dialogue? lol and also Serana at this point will never be a marry option

I think I figured out what the problem is. I was in the process of building Lakeview Manor and had the "Shrine of Mara" available for building. I built it and bought a new Amulet of Mara, and eligible candidates now have the option to marry.