Nix and Dawson have both had issues with addiction. – but they are at two different points in their dealings. Their relationship gets off to a rocky start when one of them has gone through the worst and is on the other side sober and the other is still in denial and struggling with how to fix his life. It will be a long journey, but there is help along the way.
Nix was in control of his sobriety and felt that he could help Dawson confront his demons and get started down the difficult path to sobriety. Having someone there for you who has been down that road and knows how difficult it is helpful. They likewise begin exploring their tentative feelings for each other, and the intense chemistry and connection more than addiction.