The sooner you realise that it’s never going to go back to the way it was, the sooner you can move forwards.
Understand that your loved one will always remain active in their addiction while you continue to permit them to have it.
There is very little hope for them to change, if you’re not prepared to first change your attitude towards their addiction and to move into a position of no longer accepting their behaviours.
This is called “Tough Love”