I'm jealous of all my friends in relationships because I'm so fucking lonely but also I know damn well I'm a terrible romantic partner so it's not a bad thing to be single. Still it sucks to be caught between "want relationship" and "I cannot inflict myself upon others." Not to mention all my crushes I have will never go anywhere.

I'm not sure we are our best, most favourable judges when it comes to ourselves, so if you think you aren't a good romantic partner that doesn't mean you really aren't. So I would not instantly dismiss a relationship out of hand, especially if someone wants to have one with you. Just let it play out naturally, maybe one of your crushes might actually go somewhere.