wants me as a partner for the comfort, support and care he receives but seems to want intimacy with others.
To be honest most survivors do not understand intimacy. It is the one thing we avoid before we begin to heal.
By nature I am a nurturer and want to run back into what seems to be an abusive and non loving environment. DAMN!!!!
This is the first indication that you are a Co-dependent. You need to understand that you are in an abusive relationship, and if something doesn't change, someone is going to get hurt, namely YOU.
How can I support him and not feel like a victim.
You need to learn to disassociate your self from this abusive situation. A Decision needs to be made at this point. Look after me, or I suffer and stay and look after him. Choice is not simple but it is yours to make.
You cannot decide that HE should heal, only he can do this. You can however make a decision that you should heal, This is with in your power and ability.
I am not saying that you should cut yourself of from him, but you need to look after yourself. Once you are strong, then you can support him.