The following is one of my favorite poems of C.S. Lewis. It was written later in his life while his beloved wife was dying of cancer.
All this is flashy rhetoric about loving you
I've never had a selfless thought since I was born
I am mercenary and self-seeking through and through
I want God, you, all friends merely to serve my turn
Peace, reassurance, pleasure are the goals I seek
I cannot crawl one inch outside my proper skin
I talk of love, a scholar's parrot may talk Greek
but, self-imprisoned, always end where I begin
Only that now you have taught me, but how late my lack,
I see the chasm and everything you are was making my heart into a bridge,
by which I might get back from exile and grow man...
and now the bridge is breaking
For this I bless you as the ruin falls
the pains you give me are more precious than all other gains.