I had two periods of my life - one right out of college where I lived in a very boring, small rust belt city, and one where I lived and worked for about seven years in a Midwestern college town, where I played with a lot of men that were straight or married.
I am not a person that thinks every man is gay, or that somehow a wedding ring means 100 percent heterosexuality. But I was a very eager cocksucker, and I liked mature men, often the kind of guys that were not getting attention from their wives, and apparently for some, knowing a guy wanted to suck them off no strings attached, they took me up on the offer.
I did blow a cop once, but he wasn't a young stud rookie. He was an older Polish daddy. I've posted about him here before. Physically handsome, tall, what we used to call "bruta bella" (so rough/ugly he's handsome.) That one happened in the front seat of his cruiser. Also blew a daddy type who was a Marine recruiter. Again, not one of the guys out of a porn story, but still hot to me.
When I lived in the old mafia run rust belt city I would often go to a straight bar that was kinda friendly to all, theater people would be there, singalongs, all that. I can remember three different times being there, and striking up a conversation with some handsome guy, older and married, and ended the night each time with the gentleman of that particular evening putting his cock in my mouth. One very handsome gentleman who reminded me a bit of Alan Rickman gave me a hug before he left, with tears in his eyes, and told me "You made me feel like the hottest man in the world, and that was a beautiful gift." (This was the same man who, after telling me he was pretty sure I was flirting with him, said "You're adorable, but you're not fooling anyone. You sort of have "I suck cock" written on your forehead!")
The rural town was later on, around the time of Craigslist, more Internet driven, more transactional, I guess. The guys knew they could get no-strings head and there was a lot of them. I wasn't a slut by any means but when I went fishing I didn't have to wait long for a bite. A few really hot married/straightish guys there, the best being an assistant coach of the college's basketball team. I think that guy wins hairiest man I was ever with AND the guy who came the most.
I have been at a few business conference type things filled with guys who were open to playing with female and male attendees there. I didn't do anything there, though (don't shit where you eat, etc.)
I can't say that I ever made it a point to go after a guy who was married or identified as straight. My thing was that I liked older men, maturity and/or confidence were turn ons and so were guys who were sort of relaxed about their identity (not trying too hard to be butch or a hardass or anything like that). Also, I was never a super pretty twink or jock, and never really had much luck in gay clubs or with gay men, so I hung out where I felt welcome.