I think it's not our responsibility to save anyone.To love someone in the hopes that your love would save them is no different from any other forms of expectations.
But what we are responsible for our own actions and the state of our own minds. If we pay attention to them an continuously evolve, every action of ours would be fruitful and would overflow as love and nurturing gestures into the lives of the people we love. That's why self care is so important and exactly why it is nowhere close to being selfish.