I have known couples who delved into watching porn together and swinging, and it can lead to damaging escalation.
Beyond that I have been in three ways, and the guys I was with at the time would have odd hang ups.
One asked for a threesome, but thought it would only be with another girl and wanted to pick the girl, and it was a girl from work he wanted to fuck with permission. He didn’t want me to bring a friend in, he didn’t just want to have two girls, he had a girl in mind when he asked.
I learned from that, and when a later boyfriend asked for a similar thing, and wanted to pick the girl, I insisted that I got to have two men, and I got to choose the guy. He was angry, telling me I just wanted to fuck another guy, being a hypocritical asshat.
Thank you for your insight here.
When my wife and I were still just dating, we decided to play the watch-and-do game with porn. We bought a Tera Patrick DVD, got home and laid out a blanket on the floor of the living room, and proceeded to watch the least sexy porn I have ever seen in my life. After about ten minutes, it got so bad we just stopped following along and did our own thing. We finished watching the movie in kind of an amused stupor of "why the hell would anyone do this?" It was the first time I ever felt that way about porn, and it was very funny to me. Also, I'm glad we stopped when we did, because the next scene involved an awful lot of spitting and slapping, and neither of us dig that.
I have had on two different occasions the realistic opportunity to have a FFM threesome. One time, it was actually presented to me by my (female) college roommate and her friend who had gotten a bit of the drunk and were feeling frisky. The other time was maybe ten years later with my then-girlfriend and her friend; it would've taken a bit of persuasion, but I put my odds at better than 50-50 (the girlfriend was timid, but the friend was quite openly DTF, to the point of uninvited fondling). In both cases, it just didn't feel right. I've never really had an interest in multiple partners, never mind the fidelity issues that presented in the second instance, and I found the whole thing quite odd. I think I'm very much an outlier as a straight dude in that regard, but I don't regret passing on those shots one bit.
Honestly, that's why I enjoy these games. They allow you the opportunity to indulge in kinks that you have no interest in indulging in real life. Porn for me is an exercise in translating sex to a real-life situation; my favorite pornstars all remind me, in some way, of a person I know in the real world and have some level of attraction to. So I can vicariously have that bite of the apple and I'm good to go. These h-games are a bit different, in that for me it's all about things quite distinctly separate from reality. I have no incestuous fantasies about my cousins or my mom or anything like that. But there's a harmless outlet to open yourself up that world that's given by these games, and I enjoy that.