I was able to express needs, by that point, in my life, as I'd been working hard to overcome a decade long relationship, where I was placing someone elses needs above my own. And the couple relationships, prior, were the same. By the time, that email friendship, reached that level, I knew that I didn't want to play into the fantasy effect of on-line relations.
What you are experiencing is far too common, unfortunately.

I was stimulating his cerebral needs, in that particular relationship, without getting much more in return, than starting to feel like I was his personal sounding board. Not that, I didn't gain a fair level of friendship, in the process, I was just over investing too much energy and leaving myself closed off to others, as I was developing feelings, that could never be expanded upon.

I like the title of your thread, Learning the HARD WAY.