AITA: My fiancé (26f) just gave me an ultimatum. Since she only dated me, she wants approval to go test the waters with other men. Is the wedding off?

We’ve been together for 5 years. Started when I was 25, she was 21. She said she never dated anyone before me due to school.
AITA: My fiancé (26f) just gave me an ultimatum. Since she only dated me, she wants approval to go test the waters with other men. Is the wedding off?
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