Pooning while in an "unhealthy marriage" seems more like a band-aid on a shattered window, thinking it's solving anything....it doesn't...
For me, I see pooning as massage therapy. I love my wife, no obvious issues that would lead me to believe my marriage is toxic. I share in the cooking, cleaning, and child raising equally with her. I am the bread-winner, but she works and contributes too. We are active (well, 'were' thanks to COVID), and travel and do family activities... overall we are tight-knit, not to worry about things falling apart...... Except for that one thing, that annoys me, like a dripping faucet in the middle of the night; that "itch".... Even though we're middle-aged, I still want to fuck like a teenager, but the wife doesn't seems to have the same energy. We have sex enough to still believe we're into each other, but I do want more. We 'talked' about how we can get more, but she seems disinterested to try; which is tragic since in our younger years, she'd do anything. But I don't see here unwillingness as a bad sign, just something to accept.....so I compensate... I turned to pooning to fill the void, and have my demands met.... in that case, I think "pooning is the cure", no different than going to a legit RMT and getting a therapeutic massage on an atrophied muscle.....
Now for the extreme case, if you were in a toxic marriage. Husband is a drunken abuser, or the wife is so high-maintenance she sinks the family into unescapable credit-card debt, name your scenario......and the only real catharsis in that relationship is to poon without prejudice. IMO, it's the wrong mentality to have. Because being such a dismal state of mind, you act only on rushed instincts. You think more with the little head, than the big one, leading to more trouble you're willing to accept, either by disease, cops, or thugs.....not to mention the safety of the other party who isn't into the trade to be one's emotional punching bag either..... Pooning for those types is just a weak band-aid to a larger issue they should solve first.