1749, (w), (w), Chapter III, http://www.gutenberg.org/files/6593/6593-h/6593-h.htm
(..) sensations of this kind, however delicious, are, at their first recognition, of a very tumultuous nature, and have very little of the opiate in them. They were, moreover, in the present case, embittered with certain circumstances, which being mixed with sweeter ingredients, tended altogether to compose a draught that might be termed bitter-sweet(..)
1898, (w), "Three Sunsets" in Three Sunsets and Other Poems, http://www.gutenberg.org/files/35497/35497-h/35497-h.htm
He sat beside the busy street,
There, where he last had seen her face:
And thronging memories, bitter-sweet,
Seemed yet to haunt the ancient place:
The break-up was very bittersweet; they both hurt to end it, but were glad it was over.
I had once before visited these three villages, Skedans, Tanoo and Cumshewa. The bitter-sweet of their overwhelming loneliness created a longing to return to them.
1935, (w), Spring Came on Forever, Chapter 43, http://gutenberg.net.au/ebooks05/0500651.txt
Over by the creek-bed scarlet-flamed sumac shouldered the silver-green of the willows, and orange-colored bittersweet crept through the tangle of wild plums.
"They had a good crop of bitter-sweets; they couldn't grind them all" (nodding towards an orchard where some heaps of apples had been left lying ever since the ingathering).