Can someone tell me what this dream means?

I apologize in advance for this being long!

Last night, I had a crazy dream. It was very vivid. In the dream, I was in a back room of some sort with my cousin (I am a girl -- cousin is a boy) and we began making out extremely passionately. WAIT. This guy was only my cousin in the dream. In real life, I wouldn't even know him. My mind just made him up. Also, in real life I have a boyfriend, whom I have been in a relationship with for 7 months. Anyway, during the dream I knew he was my cousin and I felt guilty and weird, but we were so horny and caught up in the moment, that I continued anyway. Then, something weird happened. I suggested that we have sex, and he responded EXACTLY and clearly in my boyfriend's voice, "Okay." But then I stopped and remembered that I even had a boyfriend! I realized that I was cheating on him. And even weirder is that it took me that long to realize, as if I had forgotten all about him. I also remember saying, "Maybe it wouldn't count as cheating because you're my cousin." In the dream, I ended up leaving my "cousin" because I felt so horrible and guilty. When I woke up, I felt soooo weird. How could my mind even come up with something that crazy?

I have had dreams in the past of accidentally cheating on my boyfriend and then later realizing it as if I had forgotten about him. I love my boyfriend to death and would NEVER cheat. Does this mean anything? I am extremely confused and I feel guilty.