Do I need to repay my ex fiance for the money he spent on my engagement ring which I lost over a year ago now that we are mot getting married?

I lost his ring & was afraid to tell him, so I bought a new ring of almost the same equal value, over a yr ago to replace his. Now we are not getting married & splitting up. He wants his ring back. He does not believe me when I say I lost his because he was unaware I lost it in the first place. Do I need to repay him for the ring I lost??