Fifi, it DOES certainly work that way - exactly as you described. However, I still say it goes back to 'learned behaviour'.
OK, so let's take it for granted that none of us want to grow old alone. Isn't that the fundamental reason why society looks upon us as some kind of freak if we are single?

We spend our childhood being dependent on our parents and our family, then, as soon as we are old enough to leave home, we are encouraged to find a partner with whom we can be dependent/co-dependent.

I can only speak from experience, but for most of my life I was the kind of person who hates their own company. Living alone was the stuff of nightmares. My ex-wife and I were together for 27 years, married for 25, and when it all came crashing down I was petrified.

I was one of those 'sad bastards' that joined dating sites etc, because I was too scared of being alone. (to no avail I might add)

Now, after 3 years of living alone (two years in China), I am quite happy. Now it's the thought of sharing my life with someone else that scares me. In other words, I've gone 'full circle'. I firmly believe that it's all down to peer pressure and learned behaviour. That, and being conditioned into a society that tells us we are somehow 'strange' or 'odd' if we make conscious decisions to do something a little 'outside-the-norm'.

I don't think I'm a selfish person at all, quite the opposite in fact, but having the freedom to do as I please without stopping to consider the needs, feelings, or wants of a partner, is something that I am not only enjoying right now, I'm actually relishing it.

How long that will last is anyone's guess, but remember this:-

"Loneliness is the pain of solitude; Solitude is the joy of loneliness" - Paul Fox.

In other words, it's all a matter of attitude and mindset.