Love is not allowed, pain is not forgotten, let go, where does the loss come from?

The Complete Poems of Cangyang Jiacuo. Love is not allowed, pain is not forgotten, and letting go and losing is unwilling. The original sentence is that the Buddha said that there are eight difficulties in life: birth, old age, illness, death, love separation, resentment for a long time, begging and letting go. Later, it was adapted into what it is now through the internet. Judging from the whole poem of Cangyang Jiacuo, it probably means that you want to get it but can't get it, you want to give up but can't do it, and you finally get it but don't know how to cherish it.