This is a 100% true story, that happened about 10 years ago, when i was on holidays with my ex in Puerto Rico, Gran Canaria. I was 24, she was 21. Its safe to say i was punching well above my weight in going out with her, i'm not bad looking, but she was genuinely gorgeous, a real head turner. She had black hair,chocolate brown eyes, tanned skin, size 10 body with 34c tits, lovely arse. We had what was at the time for us a decent enough sex life, obviously since then i've learned a lot more about sex, but i thought then she was happy enough with me.....Anyway, the resort we were in was very quiet, we kept to ourselves for the first ten days, then on the second last night when we were in a local bar we met 2 lads that i worked with at home.Now these lads were very close, best mates, spent ALL their time together, so much so that everyone i worked with, including me, thought they were gay. They never spoke about girls or going out on dates, they just worked together and then spent all their time in the gym together, they were both muscle men. So thats why i didnt feel uneasy about inviting them over to my table to meet my gf. For the purpose of this story ill call them dave and gary, and my ex lisa. Lisa looked amazing in a little pair of tight white shorts showing off her arse, and a pink boob tube showing her tanned and toned stomach, and her pert tits. Dave and gary were both wearing tight tshirts showing off their ripped bodies, lisa loved guys like this but i wasnt jealous cos they were gay, right??Anyway, we all got along fine and the drink flowed and flowed, the lads getting me shot after shot.I cant remember who suggested what but i was soon staggering back to our apartment, helped by the lads no doubt, where i crashed out in bed. I remember waking up some time later, still very drunk,just wearing my boxers, head banging, dying for a drink. I didnt cop that lisa wasnt beside me in the bed. I slowly walked towards the living room area, where i was greeted a site that i'll never, ever forget: the cushions were laid out across the floor, lisa was on her hands and knees, naked, dave was naked, pounding her from behind, doggy style, and gary was face fucking her at the front. I froze in shock, the room was only lit by a couple of lamps, they couldnt see me, they were too busy to notice anyway! Now i'm no wimp bf or cuckold, and a strange mix of emotions came over me; on one hand i wanted to kill these guys for fucking my gf, nad her for cheating, but on the other hand i was feeling very aroused at the sight of 2 well built guys really fucking her hard, and seeing her body treated this way,and lisa really enjoying it. Dave stopped fucking her, and rested for a while, stroking his cock, which looked about same as mine, 7 inches. Gary came around behind her, now his cock was fat and very long, id say 9 or 10 inches, it was a whopper, i was was dying to see how lisa would cope with it. He rammed into her, shifting her postion to face dave on the couch. She was groaning in ecstacy, he really picked up the pace now, fucking her like an animal, much harder than i ever had, she was urging him on, the lads started calling her names, this really turned me on as i watched in secret, my beautiful gf getting fucked like a whore, and she really loved it. They both soon came, gary pulled out and spunked all over her face, soon folowed by dave, i was pissed off cos she never let me do that to her. She slumped to the floor exhausted and satisfied, the lads laughed and said i bet he never fuckes u like that! I crept beck into the bedroom, my heart racing, my mind too. What should i do? What should i say? In the end i said nothing, we flew home later and i never mentioned it to her. We broke up a year later, not over this, though i often wonder if she craved big cock since then??