How to fix Unity spawner?

Question

Unity

The objects generated by the spawner are destroyed by the user, but if the 1st object (which is duplicated) is destroyed, then the objects stop spawning. How can I fix it?

using System.Collections;
using UnityEngine;

public class Spawner : MonoBehaviour
{
    public Transform SpawnPosition;
    public GameObject Watches;
    public float TimeSpawn;

    void Start()
    {
        StartCoroutine(SpawnSD());
    }

    void Repeat()
    {
        StartCoroutine(SpawnSD());
    }

    IEnumerator SpawnSD()
    {
        yield return new WaitForSeconds(TimeSpawn);
        Instantiate(Watches, SpawnPosition.position, Quaternion.identity);
        Repeat();
    }
}