He masterbated to a pic that's not me

So my husband of 8 months just confessed to me of masturbating to an image of a random woman. I just don't know how to react. This makes me feel disgusted but it's also very heart breaking because we are newly weds & I thought I was enough for him. I thought our sex life was good. I'm usually the one who wants it more than him. I always throw myself at him. This makes me feel so insecure of myself. Am I not beautiful? Is my body not attractive? Do i not satisfy his needs? I feel like he has cheated on me. I feel betrayed. What should I do or say?