You also just refer to her by name which would probably be more polite. . Another pair of terms I found is inamorato (male lover) and inamorata (female lover).
He's not a boy; I'm not a girl; and there's a part of me that feels like we have plenty of pet names (I probably call him “babe” more than I call Bae, which short for "babe" or stands for “before anyone else”, is another option.
Girlfriend synonyms. Top synonyms for girlfriend (other words for girlfriend) are sweetheart, lover and girl.