Wise words, and interesting to see Benatar's asymmetry used in a relationship context. The end of the last one I was in utterly destroyed me, psychologically.
Same here. I only had one long relationship. I still see no red flags in my ex, neither did my parents (of course now they claim to see it in hindsight, lol). It was many beautiful years, and kept me emotionally secure. Then it suddenly ended and 6 months later still feels like my brain is being slow cooked. My mind can see no purpose in living alone or finding a new partner (in fact, I believe had I chosen a different person it would have ended even worse). Now, sure, before I met my ex I was also mentally troubled a bit in loneliness, but I had hope. Now I see no hope because I will always have in mind that a new relationship could end (it's like a deterrent because I want to avoid pain again). I would in fact look for red flags, perhaps invent them, and thus destroy it for that person. So I would rather go back to loneliness before, because I at least hadn't experienced the pain yet.
It's like a drug. It's fun for a bit, but then wears off and it's just something you take daily. But when you go cold turkey, the withdrawal pain is some of the most horrific pain and you regret ever having tried it. In fact, the reason ex-addicts often relapse is not due to the pleasure of the drug but rather to mask the damage the drug has done (it is said that the first "high" is never achieved again by the addict even when they relapse).
As for Benatar's assymmetry applied to relationships, I apply it because studies show how separation can be just as damaging as losing a loved one to death. In fact harder, because society does not give the broken up person a break. Studies also show children are more affected by divorce than death of a parent, no joke. I believe the way we humans act towards each other can physically alter the brain and thus incur actual brain damage. Think PTSD war veterans who have to live on with a permanently overactive alerted amygdala by just seeing stuff for a few months. I believe the "neurotypical" brain is also to some degree damaged as it hardens in adulthood and then ages. All of this is due to how humans
relate to each other (this is the misanthropic argument for anti-natalism, and I'm definitely not claiming that I haven't taken part in hurting others as well!). The fact that over half of relationships end and cause more or less damage does not mean it is a "normal" thing the human mind can withstand unscathed (just like the fact that almost everyone knowing someone who has been victims of crime or war doesn't and shouldn't normalize war and crime). "Just get over it".