Whilst you may have had your religious marriage take place at the same time as your civil legal marriage, they are two separate processes. So, when the relationship ends, you will need to obtain both a religious and civil divorce. Otherwise, you may remain religiously married to your partner but not legally, or vice versa.
How do I get a Jewish divorce?
Once two parties have separated, in order to divorce, the husband must provide his wife with a Get. A Get is the document that formally ends the religious married under Halacha (Jewish law). A Get will be prepared on instruction from the husband and doesn't require him to cite any reasons for the divorce. This is different to the civil divorce process which would require him to confirm the marriage has irretrievably broken down.
The Get will be prepared by a Beth Din (also called Beus Din or Beit Din), which is a religious assembly of 3 rabbis. Either party can apply to the Beth Din for the Get, but it must be the husband who ultimately hands it to his wife. The Get can be applied for whilst the parties are still living together, but it can only be prepared and given by the husband once they are no longer cohabiting.