One of my greatest fears...

I had a dream last night, and it considerably affected me. It was one of my greatest fears. It may sound petty, but I'm scared of being cheated on.
The dream wasn't really that long. In fact, I only remember a scene. It was my Ozzie with someone. I knew right then (in my dream) he had replaced me.
I know my Ozzie really won't cheat on me... but the dream made such a large impact.