<human>: This has been bothering me for some time, and I don't really want to discuss it with my friends, as I feel it would be disrespectful to her.

I have a healthy relationship with my SO. We've been together for a year and a half, and it has being going great. I am head over heels for her, and she for me. We've lived together for months at a time, and since I left university have been semi-long-distance (100 miles), but still see each other every week or two for a weekend. She is genuinely the one for me, as sometimes you just know, right?

However, one thing that bugs me is that since I moved away from university, is that every 3-4 weeks, I dream of cheating on her. It is with the most random people, almost all of whom I don't find particularly hot IRL. This morning I woke with a feeling something was vaguely wrong, then on getting to work and seeing the in-house caterer, realised I'd dreamed of taking her on a date and shagging her.

It really weirds me out. I think it is because I find the fantasy, if not the reality, of cheating really hot. I once cheated on an ex years ago and felt utterly awful. But the idea turns me on. Forbidden fruit, I suppose. But what creeps me out is that it has crept into my subconscious, where I do in my dreams what I would never consider in real life. 

I'm not really sure what to do about this. I've always fantasised about cheating without ever really wanting to do it. But the dreams make me feel much more fundamentally immoral.

I certainly don't want to tell her about this, I just don't see how it could do any good.

Can you provide a brief overview of the text?
<bot>: Have healthy relationship with SO. Keep dreaming about cheating on her, but don't want to in reality. What do?