@maura2424,
He gave you the ring because he believed you were going to get married, not as a gift because he thought you were swell.
If you've decided you don't want to marry him, that's fine but give him back the ring.
Women who keep engagement rings when they break up the engagement are, to put it mildly, morally challenged.
This is a simple matter of equity and has nothing to do with etiquette .
The guy spent more than he had (usually) to give you a ring. Now you dash his dreams and want to him to continue to pay off something that only reminds him of pain?