Selfishness and the Self
The selfish act is not an act overly focused on the self; it is an act which depends upon a narrow or shrivelled sense of self or one which is overly concerned with the self as it appears in the eyes of others.
We must love ourselves - but at its best our love mirrors the best love we have for others. We want 'the best' for them - including we want them to be the best that they can be.
As the ancient Greeks observed, if we want the best for our child, it is to want them to be happy only in the sense that we want them to have led a life which is truly worthy or respect. [Hence the paradox that you can only judge someone to be happy when they are dead.]
So strangely - we must love others as we love ourselves; but also we should love ourself as we should love others.