My [M24] gf [F27] cucked me, but went further than we agreed

I (M24) was cucked recently by my gf (F27) and her former fwb (M27).

She (we’ll call her Liv) found out I was into cucking a while ago, and for a long time we fantasised about it but it was pretty clear it was never going to happen in real life.

She’s really good friends with a load of guys, including one who was her friend with benefits right up until we started dating, almost 4 years ago now. We’ll call him Andy.

We’d dirty talk sometimes about her fucking Andy, and it would drive me crazy thinking about this other guy absolutely dominating her. But I never suspected anything would come of it. Until one day, we were on a night out and then staying in Andy’s flat in his spare room. The whole night I didn’t really speak to liz that much, I was busy dancing, drinking and doing coke with her friends. So I hadn’t really noticed that she had spent most of the time dancing with Andy until the end of the night when we were getting the train back to his place. On the train she was sat between us both and she had her hand resting on my lap, but then I also noticed her other hand was on his. When we got back to his place we stayed up getting high, drinking more, then at about 3am he said he was going to head to bed, and we said we’d do the same. He went into his room, but before we went into ours, Liz stopped and told me “I’m going to go make out with Andy, ok?”. I was shocked but just stuttered out “ok” and watched as she went in and sat on his bed. From the angle I could only see the bottom of his bed, but I could see their legs interlinking.

After about 10 minutes of listening to their lips and tongues mixing, Liz came out and joined me in the spare room. She asked if I was ok and I said yes. She said she wants to go back in but wanted to check what I am ok with, as she wasn’t sure how much my fantasy would extend now it’s real life. I told her that she can suck his cock, but if she wants to go any further she has to ask him to let me watch. She agrees and I watch her go back in and I can see her straddle him, and take off her top and I see she’s in her sexiest, almost see through bra. I can see her start to bend down to him, but as she does he gets up and heads towards me to shut the door. I manage to duck away before he sees me, but then I hear the door lock and I know I now just have to trust her.

Maybe I shouldn’t have. I listen to her sucking and slurping on his cock for so long I eventually get tired of listening to the door and go back to my bed to jerk off to the muffled sounds. After almost an hour I hear them start to talk. I go back to the door and hear her asking him if I can watch, and then she’ll let him have “everything he wants”. He says no though, says he is not comfortable with it. She says she’ll just keep sucking his dick then, and it continues.

At this point I’m getting a little delirious as I’m very high and it’s approaching 5am, but I eventually I hear a change in the sounds. Less slurping, more slapping. That’s when I hear her start moaning. I put my ear to the door again and I hear her mutter words which made my heart drop: “yes Andy, fuck me, fuck that’s so good”. The door is locked and there is nothing I can do but listen as they go at it, hard and loudly, until almost 8am. I doze off a couple of times and wake up and hear they are still fucking, all night. At 8am, she comes to me in the spare room. Makeup running down her face, no clothes on apart from torn fishnets, and the telltale sign of a promise broken, cum dripping down her leg