Things that trigger me into worrying

I feel like every time someone points out something wrong about my relationship (or something else in my life), I don’t realize it until then. If it doesn’t concern me now, then I will never be concerned about it until someone points out that I should be.

For example, one of my girlfriends asked me if I ever had the gut feeling that my boyfriend is cheating on me. I never thought about that until she mentioned it. I never thought: “ooh what if he’s cheating on me?” Because I trust my boyfriend.

Since she said that, I’ve been anxious and worried. Although I know deep in my heart that he is not cheating.

Any thoughts/advice?