I've been seeing sue for about 2yrs she's 40yrs old a very quiet and softly spoken woman well that's what I thought until we went away together a few weeks ago I don't know if it was too much sun and obviously too much drink. We were in st. lucia and were having a great time especially on the beach where sue was center of attraction with her blonde hair and her big tits the locals were hanging around us like fly's on s##t. there was this youngish guy called seb who always wanted to show us around the island I knew he really wanted to show sue around and not me anyway on the last but one day of our holiday we took up his invitation. He showed us all around the places took us to waterfalls etc where sue flaunted her tits going topless while swimming I could see his eyes popping out once back we thanked him and invited him to ours for a drink later that evening, he arrived around 9pm it was a quiet place where you could walk on the beach undesterbed after a good few drinks sue was getting loads of attention from seb she had a low cut dress on and her tits were bulging out of the top I decide to go for a walk along the beach sue and seb stayed behind while I was away about 5 mins I turned back where to my surprise I could see sue kissing seb on the sofa as he played with her tits as much as I was angry I found it turning me on as I could see them clearly seb started to run his hand up sue's dress without I may add any resistance she flung her head back as he fingered her and sucked away at her tits before long he had her head held down on him sucking his black cock for all it's worth a couple of times they stopped to look out for me then carried on she sucked him for what seemed ages then mounted him lifting her dress up and pulling her thong to one side he thrust his cock right up her longing hole I could see her biting her lip as she rode him he must of shot his load up her as she fell forward holding tight onto him they tidied themselves up and I arrived backthey acted as though nothing had happened, after seb had left we fucked as usual but I could tell her hole had been well fucked, I've never mentioned it to her yet but she is already going on about going back next year.