Not gay, but I still appreciate the love from dudes who love other dudes because frankly...you guys know what's up as much (arguably more so) than horny females.
Torn between humiliation and supreme pleasure. It's not even physical. She just loves to see him happy so much, she loves knowing he's pleasuring himself in her ass. It's even better than she feels used and degraded.
Your wife is pretty much just a sex object for your bully. Nothing but a toy for him. So why would he share his sex object with you? Isn't it only reasonable you never get to see her naked again? He owns her tits, not you.