My own father (80) refers to his live-in partner of ten years as his companion. I've never heard the term girlfriend or otherwise from him. He rarely calls her by name. He has a really difficult time with names. I have winced when he has tried to as he will go through the gamut of names; me, my sister-in-law, my daughter, my cousin, and even (shudder) my mom's. He sticks to companion and I do feel badly for her as I feel she is worth a hell of a lot more than that.