Hi, following situation, my girlfriend has a new collegue who is into her. Today she is going to tell him, that it is not going to work since she is with me. She assumes that i am not aware of this.

She is going to tell me about it next week. My question is, how should i react? My plan is to ask her once if she something happened. When she says no i am going to switch the topic. Any remarks or advice how i should behave? BR,