Hehe, I like erections a lot. Maybe our humor lifted your mood a little, and that's a good thing. But to return to our topic:
I reread your OP and I did want to address this sex idea more thoroughly. You express a desire for FWBs, some plain and simple sex with another partner or partners. That might be more correctly called fuckbuddies. If it's just sex, it's fuckbuddies or playpartners. You could call it being a swinger. If it's FWBs, there's an assumption of some affection. If that affection turns to deep caring and intimacy, to love, it's polyamory.
As you might've gathered from reading around the board by now, so many individuals/couples have come to a poly mindset after trying sex with no attachment, no strings attached type things. Sex causes bonding. Swingers go to great lengths sometimes to prevent pesky old feelings of love to crop up. Many don't kiss their playpartners for example. Kissing causes several hormones to be released which cause attachment and obsession with the sex partner. Looking deeply into one another's eyes during sex also causes bonding and something that feels like love.
Since you seem to be a very affectionate, caring guy, I fear that if you did somehow get the go ahead to have sex with/kiss/cuddle/date others, you'd soon fall in love with the people you shag. This happens all the time. Of course, this would hurt and threaten your wife even more...
Our board is for people who *love* more than one, the core definition of polyamory. Feelings, emotions, not just sex. You may now feel an overwhelming need for sex with others, but once you got that (hypothetically, as of course your wife is not on board with even meaningless sex for you with others), you'd probably start to want real relationships.
Our tribal ancestors, and present day hunter gatherers, of course, do not have meaningless sex with their tribe-mates. They are all in a close knit community, trusting each other, working together, raising their kids communally.
Just food for thought. Men are trained to repress emotions (hence my earlier "sexist" comment that got River's panties in a twist), women are allowed to be more open with their feelings. But it's obvious from your posts you are a man in touch with his feelings, very loving, friendly, and well-liked (if only platonically) by your circle of friends. Allow yourself to imagine having just had sex with a sexy hot woman, the type of girl you'd be able to get it up for: attractive, intelligent, delicious. Would it be "just sex" for you, or actually become something deeper? Look ahead, imagine the scenario with your wife if you got bonded and obsessed with a new person, in the way infatuation/new relationship energy (NRE) leads us to feel.
How would that all work out, in your mind?