My misses and I have been together for some time; our sex life had pretty much dried up. We recently moved to Cheltenham and my misses started acting a bit different. Since I was 16 I had been wearing boxers, now at 33 I still did, or at least until I moved here. One day on returning from work I had a bath then headed for the bedroom for some boxers. My misses had thrown them all out and replaced them with white briefs. When I asked her about them she stated she never liked boxers and she thought i'd look really hot in briefs. A few nights later we went out for a drink, and after she said she wanted to walk through a park. So we did; no sooner had we got in the park than she started touching me, there were a load of old drunks watching us from a distance. Without much warning she suddenly pulled down my trousers leaving me stood there in these briefs. I was both embarressed and aroused, briefs are an embarressing form of underwear and to be exposed in them in front of about 6 drunks was kind of degrading. She asked me to finger her telling me not to take her knickers down, so i pulled her skirt up and underneath she was wearing grey cotton knickers (not thong just plain knickers) now normally she wore a thong, which in honesty I did not think looked right on her, so it was a bit of double excitement as these knickers were sort of "innocent". So there we were both stood in a public place in our slightly embarressing underwear her wanking me off and me fingering her, we both came quite quickly and left thinking nothing of it. A few days later we went for a walk up the hills, we stood at the top admiring the view. I was leant against a tree which she pushed me firmly up against. She moved me round the tree to the other side and to my shock, we were in a dogging area. "I have a suprise for you" she said handcuffing my hands around the tree. I was stood facing forward handcuffed to a tree, she then undid my shirt and opened it as wide as she could. Then she undid my trousers pulling them down and off me. So again I was stood in my underwear, a pair of embarresing briefs. This time I could not do anything and we were being observed by about 12 people. She went off to the group and spoke to them, one couple were fucking over the bonnet of a car and she was in a discussion with them that was quite surreal. She then went and sat on a patch of grass just watching me. After about 5 minutes, this woman in her 50's came up to me and just slipped her hand in my pants. Although she was ugly I got very arroused; and just like that she started wanking me off. Faster and faster and again I came quite quickly. My pants were soaking wet and dripping with cum. This woman said that she would see me again and walked off. Then a guy and a woman came up to me, I was not capable of getting a hard on again. Or at least thats what I thought, this couple were in there 20's and she said "I like your pants" her partner said so did he. She then came up to me and just slowly started stroking my balls through the material of the underwear. Occasionally flashing her knickers at me, while this was happening the guy took pictures of us on his mobile. Finally she pulled my cock out and slowly kissed it with her mouth; and before I knew it I was as hard as iron again. But then the shock came, when she looked at the guy and said "over to you" She pulled his trousers down to his boxers, and I thought jesus he is going to fuck me. I'm not homophobic but this just was not a issue that I wanted to encounter. I consider myself to be straight but anal sex with women or men just is not my bag. Luckily she just started wanking him off, so I began to get more calm. This calmness evaporated when he suddenly slipped his hand in my pants and started wanking me off. I wont deny it, I really enjoyed it. Two more encounters occured, one in which my misses wanked me of in the garden while i gave her oral, both in full knowledge that our weirdo neighbour was watching. And on the final occasion we lay in a park her in white cotton knickers, me in my briefs just stroking each other gently (not proper masturbation) while a man in his 50's watched us and wanked off. But now its all stopped, she has gone back to being non sexual again leaving me with this bizarre underwear fetish. She has opened up a can of worms that I cannot close leaving me very, very frustrated.