"Live happily ever after" is a common phrase used to describe a happy ending to a story. However, there are several synonyms that can be used to describe a similar concept. For instance, "live joyfully ever after" is a great substitute since it conveys the same positive sentiment. Another alternative is "live blissfully ever after," which indicates a life filled with joy and contentment. You can also use "live in perfect harmony" to describe a couple or a family who live in peace and happiness. Lastly, "live in everlasting happiness" is a synonym that emphasizes a long-lasting and eternal happiness that will never fade away.