NO, WTF. Wanting to see your wife fucked by another man is not something common at all. It's just something that's induced by watching porn - when you're watching porn you're literally training your brain to be aroused when you watch someone you're attracted to get fucked by someone else. Porn literally trains you to be a cuck.
You used to literally get killed for having sex with someone that is someone else's spouse. Partner got killed also. Still happens actually.
WANTING TO SEE YOUR PARTNER GET FUCKED BY SOMEONE ELSE IS NOT NORMAL AT ALL, IT'S DEGENERATE.
@HonestyMatters Your husband needs professional help. He is escalating the behavior and it's an abnormal and unhealthy behavior to begin with. There's probably a lot of tension between you and understandably so, which is why he probably doesn't want to confess everything to you. A therapist however will help him. Just make sure it's not a degenerate "new age sex therapist" , which is what sadly most therapists in US/Europe are. This new breed of sex therapists actually encourage "experimentation" and sexual degeneracy.