My Wife and My Best Friend Have Great Chemistry, and I Can’t Stop Thinking About It

I’m a 29-year-old married man, and my wife (27F) and I have been married for two years. We don’t have children yet, so we spend a lot of our free time socializing with friends.

One of our closest friends is a guy (31M) whom I’ve known since we were teenagers. He’s single, attractive, has a stable career, and while he can be socially awkward at times, he’s generally a great person.

Over the past couple of years, I’ve noticed that my wife seems to genuinely enjoy spending time with him. They’re both fairly introverted, and they appear to connect well in conversation. As a result, the three of us often hang out together, and he’s become familiar with my extended family as well. It’s not unusual for us to meet up for breakfast, casual outings, or family gatherings.

Recently, I’ve noticed something unexpected. During intimate moments with my wife, I sometimes find myself imagining her and this friend together, and I seem to enjoy those thoughts. It’s not something I ever consciously sought out, and I’m not sure what to make of it.

Is it unusual to have these kinds of fantasies involving a close friend and a spouse? More importantly, is this something that can remain a harmless fantasy, or could it become damaging to my marriage or friendships in the long run?