This story contains some bi male content as well so if that's not your thing, you may want to pass.
*
A few years ago my wife worked as a marketing analyst for a firm in Denver. We were living in Fort Collins at the time so she was commuting every day. It was a good job and she made good bucks so the sacrifice was worth it. Her schedule was a bit erratic from time to time as different projects demanded she be available when needed. It was during these long hours that a co-worker asked her to go out to dinner with him. He was also married and had to work the strange hours and since it was just a bite to eat after work before going home, she thought nothing of it.
Now and then they would go out to lunch after that and started to enjoy each others company. I met Dennis shortly after the first time they went out for dinner and he seemed like a good guy. A bit intense but cool. He and I hit it off and he told me he really liked Pam and that she was a lot of fun at work. After that, he and I got together from time to time when I made it down to Denver. We never mentioned this to Pam and it was a way for me to know how she was doing or if she was ever having a bad day. One evening, Dennis and I went out and had a few beers and I guess our tongues got a little loose. He let slip that he thought she was sexy and that if she wasn't married, he'd try to take their relationship further. I let slip for him not to let that stop him. It was an awkward few minutes after that when we both realized what we'd said.
He finally continued, asking me if I was serious. I thought about it for a while and finally figured what the hell, and told him it wouldn't bother me. After talking more, we revealed some of our secrets and fantasies like we'd known each other for years. The way we were talking about Pam, it seemed more like we were talking about some other woman he'd met at work, rather than my wife. I asked him what it was that turned him on about Pam. I'd been married to her for over 20 years and knew she was, like me, just an average conservative person. He told me there was something about her that made him think there was a wild woman hidden under her ultra conservative demeanor. All it needed was to be brought out into the open. That was surprising to me.
I finally told him it would turn me on if he ever succeeded. All I wanted was for him to tell me about it. With that, the seed was sewn and Dennis proceeded to work on Pam. Now and then he would send me little updates on what they talked about, how she was warming up to him etc, etc. At first Pam didn't say anything to me about his subtle advances. Then one night after they'd gone out to dinner, he asked her if she'd ever had an affair. She admitted that she had had a one night fling when I was out of town for a couple months on business. It seems she'd gotten really toasted at a party she went to and ended up sleeping with a friend of ours. This had been 13 years earlier. Although curious who it was, I was surprised that I wasn't jealous or angry about it. In fact, I found myself getting aroused over the whole thing. Dennis and I decided that we'd keep any contact between us to a minimum for a while. At least, the contact Pam was aware of.
Finally one night, Pam and I were lying in bed and she mentioned to me that she thought Dennis was interested in her. I asked her in what way and it was tough to get it out of her. She finally admitted that she thought Dennis was trying to get her into bed. This was very touchy and I was very careful with my words. I asked her what she thought of it and she immediately replied that she only needed me. She was flattered, I could tell, but the brakes were definitely on. I decided that the best way to proceed was slowly. I emailed Dennis and told him what was going on and he replied that he must be getting to her in some way if she told me about it. She had never said she didn't want to sleep with him. Se also had never told Dennis she wasn't interested. All she did was to remind him that she was married. As Dennis took his time with Pam over the months, she and I discussed his persistence and her growing curiosity.
One night while having sex, I told her to fantasize that it was Dennis she was having sex with. She got a little pissed at me over that but I knew that at least the seed had been sewn. As time went on, we would role play now and then as part of a "fantasy". Sometimes I would have her tell me when we fucked, "Fuck me harder Dennis." At first she didn't like this but after a while, she got into it a little bit.