<human>: Condense the text into a few key points

Hi /r/relationships. I made a throwaway for obvious reasons. A little background about me:

My girlfriend and I are in college right now, we have been dating for several years, and friends before that. We have been extremely happy together and have had quite frank conversations about the future, we intend to marry when we graduate, and I have been looking around at rings.

I have not been attracted to another woman while in this relationship. Like everyone else, I have found other women good looking, but have never been emotionally attracted to someone. However, last night I dreamed I cheated on my girlfriend, and it was very detailed. The person whom I "cheated" with is a friend of mine at school as well, though we have only known each other for a year or so. I remember very vividly what we did, and how we did it, and the regret and shame I felt after it happened, and I felt the same when I woke up.

My girlfriend and I don't have any troubles besides the occasional fight. She's my best friend, and I care for her more than anyone and desperately want to spend my life with her, which is why this disturbed me so much last night. That, and how vivid this was. I remember where I was, what both myself and the person I was "cheating" with was wearing. Once again, this is someone I know, and now I feel guilty, ashamed, and a little awkward and nervous about seeing this friend again since I have thought of them (even subconsciously) in a very sexual way.

Thanks everyone, any advice is appreciated.
<bot>: In a happy, monogamous relationship, dreamed quite vividly about cheating last night with a friend, now disturbed and need advice.