cheating in dreams

On a daily basis I dream about my boyfriend going to work and cheating on me. He's not the type to do it. I trust him. But I can't help but dream it. I'll wake up in the middle of the night because of it and when I go back to sleep the same thing happens. Iv never even met any girls from his work. I feel really insecure when I wake up. Is this just me? Is there anyway of helping this? What does this mean? How can I stop myself thinking about it.