There are more interactions, and so more chances for conflict, with those that are closest to the A. Addiction exacerbates the number and seriousness of those conflicts, and generates more unresolved guilty behavior and feelings that get in the way of closeness or intimacy.
The A deep-down knows he or she is out of control, that their loved one knows it, and that their loved one may be more "in control." Projection of self-loathing.
Those closest to the A may control the purse.
They may hide the bottles, toss the drugs, count the infractions, and do all the "codie" things that further distance the two.
The A does not have a normal ability to emotionally connect with himself or herself (stuffed and denied feelings), let alone meaningfully with anyone else. Those closest to them want that connection while acquaintances generally don't. The A gets annoyed with efforts to emotionally connect by those closest to the A.