The general rule in law is that if you have an agreement with somebody and that other person breaks that agreement and you suffer a loss as a result, you can sue that person for breach of contract.
That is not however the position as far as engagements are concerned.
If I employ a builder to build an extension to my house and he takes my money but then refuses to do the work, I can sue him and a court will either force him to do the work or they will force him to return monies to me. That is not the case when it comes to broken contracts of engagement. A court will not force a couple to marry just because there was an agreement that they should marry. That would be against public policy and would not be in the common good.
The position however is different in relation to property.
If a friend gives an engagement gift to a couple and the marriage for some reason is called off, you can insist on your gift being returned to you. The same applies to the engagement ring. If for instance the groom to be buys an expensive engagement ring and books Ashford Castle for 200 guests, at great cost, he can at the very leakevinst insist on compensation. He can certainly insist on the ring being returned and he can be compensated for expense incurred in relation to the cancelled wedding.
You have three years from the date of termination of the engagement to bring an action if you cannot settle matters between you.