Where to Watch Don't Bother to Knock (1961)

Summary

An Edinburgh travel agent loses his keys and his fiancé in one night. A friend finds the keys and makes loads of copies with his address attached as a joke. She gives them to him as he leaves for a holiday. He gives the keys to several women he romances across the continent. He gets engaged again by phone and arranges to meet his fiancé at his flat, but the flat isn't empty