Hi there Cureav. If you are the child of a narcissistic parent, putting your own needs last makes perfect sense!!! This is what you are used to doing.
Now that you recognize this pattern within your relationships, it is perhaps time to shift your behavior and thinking to know that your needs are just as important as your partner's.
It will take effort and some fumbling around, but giving yourself permission to believe that your needs are just as important is healthiest and best for both you and your relationship. Take care of YOU too... not just your partner.
I wish you all the best!!