Why do couples do drugs?

This depends on the exact couple. Sometimes, it starts where only one in the relationship starts using. Then they pressure the other to take them to so they can have something in common to do together, and the partner goes along. Other times, they were both using before they got together, and the drugs may be what brought them together. Sometimes, one starts using and the other stays drunk or takes another type of drug to try to cope with the using partner and drown out the trouble their partner is causing.