I don't know whether you refer to a business partner, you are male and refer to a girlfriend or you are female and refer to a boyfriend.

You omit at least two possibilities: that he is male and referring to his boyfriend or that she is female and referring to her girlfriend. In these cases, word "boy/girlfriend" would have you interpreting the situation wrongly.

As others have commented, the fact that we do not know these unnecessary details is a feature, not a bug, of ungendered words.