When you break a piece of yourself to please others there will come a point when there is nothing left to give. This can be avoided if you are replacing those now missing voids that were once part of what you have given away. They may have not been vital, but the void will have you feeling hollow nonetheless. The answer is not to become selfish, especially if that is not who you are as a person. The answer is not to expect from others what you give so freely. The answer is to fulfill yourself just as much (if not more) than you aim to fulfill those around you.
It all begins and ends with you.