I was uncomfortable with the ownership associations.
In Dutch, the words used to describe husband and wife are, respectively, man and vrouw, man and woman. It only means husband/wife if it is used as a possessive, by putting my (mijn) in front of it. Talk about ownership associations.
On the other hand, there's the equally-used word echtgenoot, which comes from hecht (meaning close or robust) and the verb genieten, meaning 'to enjoy'. Basically, someone you're very close to and enjoy the presence of. Sounds a lot better than significant other if you ask me.