A lot of abuse victims do not want to advertise the fact that they have been abused for a lot of reasons (stigma, Stockholm like syndrome of not wanting to cause problems to their ex, believing that the abuse their fault) and will divorce without officially saying that it's due to abuse.

Abusive relationships do not only create physical injuries but also psychological injuries and when someone decides to leave an abusive relationship and divorce, it's not necessarily easy for them to come to terms with what happened.