[@pugbutter]see, my worry is that this hyper-invested attitude of mine has made me seem intensely clingy and neurotic, and that this is what is scaring off my potential RP partners, even moreso than my amateur writing and unflattering characters.

but like here's the caveat okay
i can only too quickly make the admission that i myself have historically been guilty of serial disappearing. I don't want you to get the wrong idea and think i've never done this (especially what you outlined in your own post, with people leaving profiles and then never showing up). in my case, it was the result of an unstable mental/emotional state (i am bipolar, and used to go through periods where i would get bursts of energy and join all of these things, stop sleeping, etc then find myself hopelessly overwhelmed and exhausted when it ended), sudden complications in my outside life, or writing-based anxiety (which i struggle a great deal with). but, look

- i'm not saying my disappearing acts weren't shitty -

during these times i broke down and left the whole SITE (this was gaia, which wasn't primarily a RPing site), you know, i wouldn't be cheerfully hopping around other threads or - god forbid - joining new RPs
i left the INTERNET, i would be wallowing sunken-faced in my room pouring hours in to animal crossing or sitting in inpatient or something
i usually SAID something before i left, especially if my partner and i were already exchanging replies
i didn't just fucking--
...but i understand how people can bite off more than they can chew, and end up sacrificing whatever they're the least caught up in
especially if they haven't posted IC yet, if they just have a profile or something, i can see why they might just avoid saying anything. whatever.
it's still hurtful. and it still messes people (you, hi, you're a person) up. And they really ought to at least say something...