Has any Monarch, after peacefully abdicating their throne, tried to take it back or been returned to the throne?
Definitely. The most recent example I can think of is Gyanendra of Nepal, who reigned as King while an infant in the 1950s after his father and grandfather fled from the country after a dispute with the Rana family, who were the hereditary Prime Ministers and in some respect the real effectual rulers of Nepal. When the dispute ended, Gyanendra's reign was agreed to have ended, so he effectively abdicated.
He was returned to the throne in the 21st century after a mysterious shooting spree by his nephew wiped out multiple royals. He then abdicated a second time when Nepal was transformed into a Republic, but he still has some political support and has stated that he wants to return to the throne, which would mean he would have reigned, abdicated, reigned again, abdicated again, and then reigned again.