It's not a long story but it's one that's left me confused and questioning my morals. My girlfriend Gemma had got with me shortly after splitting from her rather bad tempered body building cage fighting ex Scott. He hadn't took the split well and was even more angry when I arrived on the scene but apart from a few threats nothing happened. Anyway two years down the line and I've managed to get an afternoon off work. Knowing Gemma was at home I thought I'd surprise her and drag her off to bed for an hour or so. I let myself in quietly but once in the hall I heard rhythmic banging from upstairs. Full of dread I walked up and into our bedroom to be greeted by the sight of Scott's brown arse pumping happily between Gemma's spread legs. "What the fucks this?" Gemma seemed to struggle a bit but Scott is strong and just kept pumping his cock into her. "Not now mate" he addressed me "I'm nearly finished" and then to Gemma he said "stop struggling just cuz he's here, you know you're close". She looked at me almost apologetically but then stopped struggling to free herself and gripped her nails into his arse pulling him into her deeper. She looked into his eyes "you arrogant bastard" she spat but started bucking on his cock. She always tells me when she's cumming. She never said anything to Scott but I could tell she was. The familiar cries, her beautiful flushed cum face, arching her back up to him for deeper penetration. He smiled across at me knowing he'd satisfied her. As her orgasm subsided he picked up pace. "Come here so you can see better" he motioned me to the head end of the bed. I complied. Gemma took my hand and mouthed sorry. She seemed subdued now while Scott was fucking her furiously. Suddenly he withdrew and gripped his cock. The first spurt splashed against the headboard and I caught some spray on my arm. He then unleashed a pretty impressive load over Gemma. I was pleased to see his cock wasn't quite as big as mine. "That was good" he said dismounting and quickly dressing. He wiped his cum from around her mouth and kissed her deeply. She didn't resist. "See you soon babe" he said, she said nothing. Then to me he said "all yours mate" and left. Gemma looked at me awaiting my reaction. I looked down at my cum covered girlfriend and only then realised I was erect. I stripped off and mounted her my cock slipping easily into her wet hole. I fucked even harder than Scott had and she responded immediately. "Oh god I'm cumming" she moaned. And she did. Multiple orgasms as I fucked her harder than I ever have. Scott's spunk covered both our faces. She licked it off mine and I licked it off hers. I don't know if it was the salty content of his balls or her wild bucking that tipped me but we enjoyed a mutual orgasm and I relieved myself heavily into her pulsating cunt. I don't know if I'm weird but I've forgiven her. I haven't told her but I'd secretly quite like her to do him again