Hi Iheart,
I think it would do no harm to work with him on such a set-up.
Co-dependency kicks in when you start to act on his behalf expecting that your actions are going to have effect. You're setting yourself up for co-dependent trouble if you start thinking you can fix him, or believing his recovery depends on your efforts. But if you try and provide your husband with a safe, rehabilitative environment at home that in of itself isn't co-dependency, that's being a commited partner.
The Friends & Family forum might give you more experience and better advise. The newcomer forum is a great place for anyone and everyone to start (so we can give you a warm SR welcome) but most the people who use this part of the site are people with addictions.
Glad your husband took a first step in tackling the problem. If he were here we'd be giving him our congradulations, best wishes and support as well.
-Iz