This too shall pass is universally applicable to all situations in your life, both good and bad. All the hardships and all the great moments in your life will eventually pass. Accept this, learn the lessons, have total gratitude for them and then let them go when it is time for them to go.
"My grandmother told me there'd be good days to counter the dark ones, with blue skies in the heart as far as the soul could see. She said you could measure a life in as many ways as there were to bake a pound cake; but you still needed real butter and eggs for a good one - pound cake that is, but I knew what she meant." Rita Dove (Robert Gwathmey)