For people feeling attacked by this post...
that's okay. give yourself a few minutes. it sucks to be hit with something like this and realize the thing you've been doing, that you were taught was the correct way to be, is causing harm. That your magic "if I keep my feelings to myself, I can't hurt anyone" mantra is actually a lie. That your intense focus on making yourself useful and not a burden has been misapplied.
does it feel unfair to have your attention to everyone else's emotions at the expense of your own characterized as "sparing your own feelings"? it probably hurts to see "falling apart because my own needs were neglected for so long" phrased as a choice to "prioritise your own self-protection."
I get that.
Perception is a hell of a thing.
The thing is, regardless of why you developed these patterns (you'll have to figure that out with your journal or your therapist or whatever your process is), they aren't serving you well now.
"If they cared about me they would have–" is poison thought all around. It hurts the people who are punished for not living up to an expectation they didn't know existed. And it hurts YOU. Sure, some people are just assholes. But if you allow yourself to be open about your feelings and what you need from a relationship (and not just romantic/sexual ones), you may be surprised by how much some people do care. They just show it differently.
ALSO, you will be shocked by how many of those you felt like you were going to the ends of the earth for didn't know how much you cared. Because the way you show it wasn't what they were used to seeing, so they didn't recognize it.
So yeah. Sit with your feelings for a bit. It's okay. We're all just human and we fuck up. But then try pushing yourself to do the opposite of what comes naturally. Open up a little. And if the person really doesn't care, well, you'll find out quickly and be able to put your energies somewhere else.