I think the VAST majority of married men imagine doing this with the wife and another man. Once that thought has drilled into your brain it is hard to get it out!
This is awesome…reminds me so much of a 3some with a co-worker and her husband. He loved watching me fuck her doggy with my finger in her hot asshole, just like this guy, while hubby was in her mouth cheering me on. When we went into a DP (me on bottom in her pussy, him behind her in her ass) she was sweating like crazy from the intensity of both our dicks inside her. It was running down her sides onto me and made it even more hot!
She quickly learned to enjoy being dominated. Her big round ass looked superb propped up in the air. I would have to pause every so often to lick her sweet asshole.