Sacrificing Yourself for a Relationship

I was reading a question from someone regarding what one should or shouldn't sacrifice in a relationship. For me the succinct answer is simply that you shouldn’t sacrifice ‘Yourself’. Be you…stay you. People who want you to change or be different in any way don’t really appreciate you as you are. If someone doesn't appreciate you, then why would you want to be with them? 
In my life I have seen a lot of people mold and shape themselves to be the ideal partners for their respective significant other. Why? It’s like you’re saying that you’re not good enough. Relationships are partnerships and in a partnership there is compromise but, not fundamental change of who we are and how we identify as human beings. 
The whole notion of being compatible with someone stems from the other person being a lot like you and that you are a good match. It’s not about becoming a good match with the other person. The further you move away from your true self the harder you'll struggle feeling good about that.
Be cognizant if you are doing more than just compromising. If instead you are really giving up a part of your core identity. You may keep your partner that way…however, it’s not worth losing your self over. No reasonable partner can or should ever expect that kind of self sacrifice from you either.