Oh, I too find the similarities between our languages fascinating. What are a husband and wife called in Norwegian? In Dutch it's 'echtgenoot' and 'echtgenote', which sounds suspicially related to your word for marriage 'ekteskap' :-)

Civil unions were mostly introduced so gay and lesbian couples could register their relationship. I understand that now any couple can get officially married, only people who have issues with traditional marriage choose civil unions instead.