Loaded up your save, and I can't really see any reason at a first glance as to why they shouldn't be able to marry. I'll file a bug report of the issue in our database. Thanks for reporting!
EDIT: Found the reason at least, it's because of you being a councillor. I'll update my report accordingly.
EDIT: Found the reason at least, it's because of you being a councillor. I'll update my report accordingly.
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