Prisoners families not enough support - from Anon

Whilst it's all very good having family visits and children seeing a parent in prison; I feel in my situation that the whole thing is for show and happy families we are not playing.
My partner is in prison and we have 2 small children. He has battled with drug addiction for years and after a good spell of being clean, he is back in HMP. 
I visited him during the Christmas holidays with our children and he admitted to taking drugs in prison because he was missing me and the kids. Then I watched him spending quality time with the children and thought 'this is not enough.' Our children need a father not a drug addict. 
He has admitted to using drugs in prison so for me the chances of him coming home clean is not a good percentage and the children are back to square one. The family visits are great, very good, but the root of the problem still lingers and I feel there is not enough support for prisoners families with a loved one battling drug addiction no matter how fantastic the family visits are. That's my 2 pennies worth and let's face it, it's the bigger picture! Love to all from Anon.