Ridiculous the way Roy Devans blames his wife for being influenced by 'monogamous societal norms', as if that's a bad thing.
Yes, most people are monogamous. There's nothing wrong with this whatsoever.
What is important here is honesty. Roy Devans promised his wife he'd be faithful to her when he married her. He has broken that promise.
If people are looking for relationships and declare at the outset that they're looking for open relationships, then ok.
But Roy Devans didn't do that.