What does Ursula's wedding ring represent in The Murder of Roger Ackroyd?

The wedding ring that Poirot digs up from the goldfish pond is a symbol for Ralph Paton and Ursula Bourne’s relationship. Although Ralph gave her the ring when they secretly married, Ursula threw it into the pond after discovering Ralph’s secret. That is, he agreed to an engagement to Flora Ackroyd when his uncle requested it, hoping that would encourage his uncle to help settle his debts. Like the ring tossed in the mud in frustration, Ursula and Ralph’s marriage suffers as a result – she is furious at this betrayal, and it causes great conflict between them.