I think you are just looking in all of the wrong places.
This has happened to me not only through romantic relations/crushes, but my friends as well - someone I had liked or trusted had turned out to be selfish, manipulating and gaslighting.
The best thing you could do about that is cut ties with people who are harming you.
Then, I would advise you to improve on yourself for a little while, build your own standards and make sure you have your friends to guide you, whether it be me, some random on the internet or your close real life friends.
Once you become the best version of yourself will you attract a person who likes you for you in a way. Who would do anything for you. Its all about building standards/confidence really.