I'm sorry, but the knowledge sources do not contain any information about setting an expiry on Ory Permissions relationships. The documentation describes how to create, manage, and delete relationships (relation tuples), but it does not mention any built-in mechanism for automatically expiring or setting a time-to-live (TTL) on relationships in Ory Permissions (Ory Keto) [Manage relation tuples](https://www.ory.sh/docs/guides/cli/configure-permission-service#manage-relation-tuples) [Relationships and permissions](https://www.ory.sh/docs/keto/concepts/relation-tuples). If you require expiring relationships, you may need to implement this logic externally in your application or automation scripts.