There are several things to call a person with whom you live intimately without matrimony: SO, Domestic Partner, Partner, etc. But they are all awkward. I face the same dilemma. My SO, DP, P and I have been together for nearly 10 years, but are unmarried. So unless you have a better nomenclature, dont bring it up.
I don't think she needs you dumping on her for her choice of words at this
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