What is the origin of the idiom "plenty of fish in the sea" and when to use it?

The origin of the idiom "plenty of fish in the sea" can be traced back to the early 17th century. It is a metaphorical expression that compares potential romantic partners to fish in the sea, suggesting that there are many options available. This idiom is used to convey the idea that there are numerous possibilities for finding love or companionship. It is often used to console or encourage someone who has experienced a romantic disappointment, emphasizing that there are many other potential partners to explore.