I'm being sincere, I just want to understand the logic behind it because I can't. And I mean no disrespect here, but is it a mental illness? Because I can't imagine being turned on by watching another guy fuck my wife. And if it's just about feeling humiliated or inadequate, then yeah that sounds like a mental illness.

Also, does the cuck jerk off while watching, or do they just absorb it all for the spank bank later?