Been in an LTR for about a month

im 19 shes 18 and shit has been good. The dynamic is good, shes very submissive and clingy which I do like.

However, sometimes she will bring up how a few weeks before we were official she was doing shit with someone else, almost like a reverse dread technique. I act aloof and unbothered but this does piss me off.

Do I tell her when she says shit like this it makes me lose attraction for her? Or ask her to just flat out stop?