Dreams are dreams after all, and many dreams mean nothing.
In fact, dreaming that the necklace is broken doesn't necessarily mean that your necklace will be broken in real life.
But you stressed that the necklace was given by your husband, so you think it is unique, don't you?
But I want to ask you: What is your relationship with your husband now? If you two have a good relationship, there is no need to think the worst and toss yourself! Don't you think so?