Setting boundaries and protecting your own peace. When is it healthy and when is it retaliatory?

I, F33, have walked a pretty traumatic path in life. I have been accused of being "toxically independant", was recently pointed towards "Eldest daughter syndrome" and have, more than once, caught myself neglecting my own needs to facilitate those of others.

Now I know better than to use those buzzwords as a guiding light in life, bur I do find them to be suitable descriptors.

As I am recovering from quite the fallout with my partner, where his setting of boundaries left mine trampled, my needs unmet and absolutely no closure I am forced to reevaluate my way of approaching relationships and life in general.

I am done feeling this way. I am working towards accepting that the only person responsible for my sense of self worth, peace, safety and pride is myself.

Now, I am not here looking for relarionship advice. When two people put their foot down it's bound to clash from time to time. We are being adults about it and are moving on.

Which is why i'm here. Throughout my life I have either lashed out/shut down or ended up apologizing for my feelings/needs. Things that remain unadressed to me will fester and continue to rot whatever foundation they have settled into and end up costing me friendships, jobs, relationships,...

I end up feeling not worthy of the effort it takes to have hard conversations, like my needs don't matter, like my asking for help isn't noticed despite how hard it is for me to do so. (Not just in my relationship, in life in general).

I have concluded that the only person in charge of my sense of safety, my self worth and my peace is me.

BUT, as someone who shows love through caring for, providing for, showing up, ... how do I "pick up" what people around me "put down" without it becoming a tit for tat type of deal?

How do I protect myself from doing all the "effort" and "investing" without keeping score? How do I set my own boundaries when they upset my loved ones? How do I demand the treatment I think I deserve without damaging those around me?

Realistically and rationally I know my worth. I am intelligent, funny, ambitious, accomplished, kind, caring, protective, loving, attractive and patient. Yet, when shit hits the fan my entire core defaults to "fix the situation", not "protect myself".

The situations end up fixed, sure. But I walk away with a little less respect for myself because I allowed for me to be ignored. I walk away feeling like a loser.

I want to be better. I'm a catch to my loved ones. How can I be one to myself?