I have had several relationships where at the time I would have called the person my significant other but in retrospect there have only been 2 that have truly been significant to my life. I met my wife at a bar. A few years after she passed, I met my now girlfriend of 12 years at a farmers market where she was selling pickles and kimchi.
I had a primary care physician in the late 1990s that had been polling his patients on that his whole career, and said that a little more than 80% of his patients met at a bar. So there you go.
I also agree with your assessment on partners, I have had a couple that were important at the time, but looking back, where more like friends with benefits. Only two were really significant. One that tortured me emotionally and basically set me up for over sensitive warning flags for about five years, what a mess. The other one I married over 25 years ago.