ProblemOfLeisure:
Why I hold out hope: The last time we had sex was after I had been reading posts on here for several days. I decided to surprise her. When we started our foreplay, I asked her what her boyfriend would think of how dirty she is with me (in other words, I pretended to be a man she cheats with). She started talking about how her boyfriend would think she was a dirty slut, etc. Then it got even more interesting, as I told her I had a bigger cock than her boyfriend's and asked her if she wanted it. She practically begged. Once I was fucking her, I told her that I wanted her to tease men and get them hard when she goes to clubs for "girls' nights." She said that she already does
This all sounds very promising, but don't rush things or use this scenario every time you make love. With my wife, it started with me pretending a realistic-looking dildo I was using on her was a real guy, a pop star I knew she fancied or a stranger she'd met in a club. This planted the seed, just as you have done. The hard bit will be convincing your girlfriend that you are serious about allowing her to sample new cocks. She may think that you can't possibly love her if you're willing to let her be fucked by other men or your fetish may just be too weird for her to contemplate outside of the bedroom.
Take it slow as I did with my wife. It took a good 2 years of role-play, talking, persuasion and encouragement before my wife finally gave in to temptation and went out on a date with a customer from the shop she worked in. I unearthed her penchant for younger men and by chance this guy was 23. It was probably a case of the right guy at the right time, but the day after her 35th birthday he took her for takes after work, then back to his flat where he quickly stripped her naked and fucked her 3 times.
Peter C