True, I just think that maybe the court would see it as a gift? He gave it to her in the hopes she'd say yes and unless she said yes then he could probably get her on it then since engagement rings are usually conditional gifts.
Basically the law trumps everything and then it really depends on the state. In California, for example, if she broke the engagement, she'd be required to return the ring; but if he broke the engagement, she gets to keep it. Some states are conditional and state that if there is no marriage, then the ring must be returned. Kansas and Montana do state that it was a gift and can't be returned. Others take circumstances into account such as the date the ring was given (Valentine's day, birthday, and holidays are more likely to be seen as a regular gift).
So really, it just depends on which state they're in. But he could likely get the value of the ring back if he sued.
So really, it just depends on which state they're in. But he could likely get the value of the ring back if he sued.