This is all academic if the ring was Chloe's, but here's a summing up of the UK law about engagement rings:
The gift of an engagement ring shall be presumed to be an absolute gift; this presumption may be rebutted by proving that the ring was given on the condition, express or implied, that it should be returned if the marriage did not take place for any reason.
Basically, although it can seem unfair, this means that unless there was an agreement to return the engagement ring if the wedding was cancelled then the recipient is under no obligation to return the ring. The courts will generally say there was an implied intention that the ring would be returned if it had particular sentimental value to the person who proposed, for example if it was a family heirloom.
Source :
http://www.nelsonslaw.co.uk/site/new...ment_ring.html
It's different in other countries and in different state in the USA.