Building on the above ...

There is this person in tango class that I see regularly. I fell for her. We see each other a few days a week (three, sometimes five) and I can't put her out of my head. I did not know she had a (bad) relationship (that lasted for 5 months) at first and ever since they broke up (almost two months ago) I have been more stressed around her than before.
I discuss this with my therapist and what she said last week is that she sees two people gradually growing towards each other (we talk more and more, she takes a detour when cycling home, she drags me to all sorts of events, asked me to join her for the tango weekend of our dancing school). I do realize that all my therapist has to work with are my observations (and possibly some confirmation bias or wishful thinking).
We went to a tango event last night. A guy who drove, she and me. She almost exclusively danced with him. I proposed to go for a bike ride a few weeks ago and she suggested to wait until the weather turns good (that was in fact a good idea). They were talking about going on a bike ride on her initiative. I think it is clear where this is going. And this is what happens all the time, every time I fall in love somebody else turns out to be more interesting.

All this makes me wonder about myself. The difference between us: he's a lawyer, he has a job, he is better at the type of dance music - not the classical tango music - they were playing yesterday; Overall, he's less tense, I guess in a way "more fun".
I could start to rationalize what happened yesterday, saying that we meet more often, that we have great conversations, we dance very nicely together on the more classical music but I am not blind either and I saw what I saw. Maybe tonight in class, things will be different but I will be hard pushed to brush this off my shouders.

This again brings my original question to mind. Am I really less than everybody else?

And then again, I might have to reconsider other things. I meet very few new people. The next meaningful encounter might be years in the future. That is why, I guess, when I develop feelings towards somebody, it always cuts so deeply. But how can I build up a social circle when I am always so insecure?
And regarding relationships ... should I start dating online, start a relationship and then hope to fall in love?