When people leave, never fixate on the one who is leaving or who has left.
There were people in your life who were there before this leaving happened, and there will be people in your life who will be there after this leaving happens.
Leaving, like staying, requires sound decisions, yes, but they both also require the hand of fate.
Would it ease your heart to know that whatever happens to you in this life, the good, the bad, the abandonment, the unions, the love, the pain, the sorrow, the epiphanies… that all this was written for you long before your soul was given life, long before you came into existence?
Perhaps, then, those who leave were meant to leave. And those who stay were meant to stay.
It was meant all along.