Most Helpful Guy
Maybe he just assumed that you guys already had a title. Maybe he felt no need to clarify it.
If you want clarification, just try to get it outta him. Maybe tag him in something and give it a heading of "i love my BF" or something like that.
Most Helpful Girl
maybe he feels like he doesn't need to explicitly say it. you could try to coax something out of him, like to get him to say you're his girlfriend maybe? usually, if you're kissing, and its exclusively just you two, it means you're dating, but you should always have a healthy talk and clarify. its not as awkward as it sounds dw :)