<human>: Hey people, My GF and I are really in love and are both very confident in our relation ship.
She was shy before to try anything else than normal sex, but I always slowly talked her into advanced things (vibrator, anal sex) and once she tried it she likes all of it now. I am abroad now for work, she at home.
Today she was texting me in the morning that she had a dream about cheating on me with another girl, and that she even had orgasm in that dream that woke her up. We were talking about it and she admited she liked it a lot. After like hour of texting (and me convicing her that Im ok with it) she admited that that fantasy turns her on, althought she never even thought about it before. The dream just let it all out. She never had any bisexual experience except one kiss with friend.

She now accepted that we might bring another girl to bed, but she is quite jelaous. She stated sevral times before that thought of me having sex with another woman would brake her heart, and it still pressists after this dream. She and I are ok with her having sex with another girl while I would watch, but later she was talking about me having sex with her  from back while the other girl woul be pleasing her from the front, which Im okay with too. 

We are now both pretty much excited about this, even though I know I wont be allowed to please / get pleased by that other girl.

I would like to ask if you have any experience with this situation. Since we both want it and are sober while talking it trough, is there any harm that could lead from it? As much as I want this happen, I dont want it breaking realtionship after just because of something I dont forsee.
Have any of you tried *threesome* like this before, where the other girl was just for her? What are your experiences? Any advices?

Can you give me the gist of the text in a nutshell?
<bot>: Girlfriend want another girl in bed for her, but not for me. I want it too, but I worry if it could somehow damage our relationship.