Following situation:

Girl I am currently seeing is actually a pleasant surprise in comparison to the other countless trashy girls I fucked.

She wants "more" than we are now. Basically not a single red flag which ironically should be a red flag itself.

Now this girl is part of one of my social circles, though no one knows we see each other. This weekend my best buddy told me that the girl was over at this place which is nothing fishy, as we are all pretty close in our friend group and see each other often which this is nothing out of the ordinary.

Then came the shocker: He told me that she slept over at his place because there was no way for her to get home anymore as it was late and middle of the week. And well, he told me they made out with each other. Keep in mind he doesn't know that the girl and I see each other.

He is my best friend and in no way does it damage my relationship to him as he doesn't know and is at no fault. I am much rather disappointed by the girl. I asked if they took it further but he said "Nah, she didn't even want to undress".

I don't have hard feelings, but I would lie if I said it doesn't sting a little.

I don't know how to proceed. On one hand I considered to simply tell her that we won't see each other anymore without a concrete explanation.

On the other hand I could just hide the fact that I know and treat her as a plate, be her "first one" and giving her false hope of "more".

The situation is special because she is 18 and is still a virgin. She is totally into me and the thought of being the first one and molding a girl is trilling me. I'm early 22's if anyone cares.