How much sacrifice is too much in a relationship?

Recently engaged, I find myself in a situation where I’ve suddenly realized that I have compromised on some significant topics which I previously held dear; the most tragic is the abandonment of a close friend. The choice to do so is a direct result of my partner’s judgment of the friend (based on minimal interaction). The friend is of opposite sex, and attractive, but I’ve always considered her to be a “little sister”.

With my recent realization, I have a developed a desire to repair the damage, but that does not seem possible due to my partner’s feelings towards the friend.

Have you ever sacrificed “too much” for a relationship or witnessed such an event? Was it realized too late? Was it a recoverable situation?