I'm kinda with you there. The focus on cheating as a way to add spice, rather than characterization, is grating after a while.
While I'm actually titillated by cheating stories I agree with that, too. Cheating, by itself, is a tired setup and bland.
Cheating when it happens among characters who have enough depth and complexity to have cheating
matter... boom.
Sang Froid is a cheating story done well and concisely. Dude walks in on his wife and his best friend. All the expectations are there: her guilt, the friend's casual and unsurprised reaction like he'd planned it (but, perhaps, it's a bluff), and the dude's shock. The art and writing highlight the wife's confusion and guilt as she reluctantly tells a story, entirely from her perspective, on how this affair started and is perpetrated. The friend makes an indecent proposal. Mystery, tension, conflict. And we find out why these two men are best friends. It's clear what the wife wanted (or, rather, DIDN'T want). It's clear what the friend wanted. We learn what the dude wanted (but wondered, for a moment). The cheating mattered (to her) until the mind control... and is really just a detail in the true conflict between dude, his wife, and the friend.
Jim's Wife is a cheating story without any heft. Dude invites his hypnotist best friend to help his wife overcome insomnia. Wife expresses concern that "something might happen" but the dude reassures her that he'll be right there the whole time. The friend instantly turns her into his on-call sex slave and makes dude an enthusiastic cuck. Because we all, generally, understand that hypnosis doesn't work this way... they all got what they wanted? The cheating doesn't matter, it was just a detail... there is no conflict between dude, his wife, and the friend!
Anyway, when it comes to mind control and cheating there's a whole world of stuff to consider beyond just the adultery. I'd be more worried about my wife being Upstream Color'd!