[Serious] Relationships: Finding your perfect match and then losing them.

[Porcupine]

tack, TA, dave.. whatever, I'm not picky.

You're looking at the wrong sampling. How many people to you know and come into contact with in a single year? Of that your relationships with them are of what magnitude, 1/9999 ?
The problem is not that when we focus our attention on what we can will or control  it comes from a narrowing of vision. You're putting on blinders for those 10 relationships to the 100000 other relationships you could be having, because of our ability to only focus on such a small area we can socially control. That's the definition of what "many fish in the sea" is all about. It's not you and your 5 relationships in a little pond, it's 5 little fish swimming in a group in a school of fish in a vast sea of life. We can only see our little pond though. Opening up to the possibilities that those  minutes coffee conversations with a stranger could lead to lifetime of contentment and happiness is what you're blinded to. To answer your question... regardless of the other topics you asked "then what?" My answer is to open yourself to possibilities and engage with people in your life, lots of them (and not just the ones you're comfortable with).  Get uncomfortably close and personal, test the waters, give, seek, love, learn and grow.

I'm rather confused and don't think I follow but perhaps it's because I'm a determinist?

I'm saying that I certainly don't expect to have more than 10 meaningful relationships in my life. So 10 is the maximum sample size. It seems that the sample size is hugely bigger from your POV because you see multiple branching pathways and many possible futures rather than just one possible future.

I could be wrong, but please let me know if I have understood you correctly.