Idiom: 'TO SLEEP LIKE A LOG' = "(informal) to sleep very well". Remember which Beatles song has 'sleeping like a log' in the lyrics? It rimes with 'working like a dog' in "[It's been] A Hard Day's Night"!
“May-December romance” or “May-September romance” is a romantic relationship where one partner is a lot older than the other. Example: The man and his girlfriend were involved in a May-September romance.