Even worse and NO solution is she's gay?! yaeh. My brain has gone there, too
There have been several examples of that on this very forum. A wayward woman is in full-tilt "exploratory" mode, and it's not uncommon for them to test out "playing for the other team."
Not that there's anything wrong with that.
It would also explain what you -- who knows her best -- felt was a genuine expression on her face when she discussed what her girlfriend did for her?