It may be difficult to tell for sure that someone is being abused, as abusive actions and behaviours often do not take place in front of others. This website provides signs and symptoms which may indicate that someone is being abused.
Domestic Violence and Abuse: Signs of Abuse and Abusive Relationships
Noticing and acknowledging the signs of an abusive relationship is the first step to ending it. This website contains signs that someone may be experiencing relationship violence, and contains resources to get help.