You need to read DR again.. MWD made it very clear that their negative attitude is a product of how they FEEL about their marraige... HOPE is what is missing...
WHen you feel hopeless, your attitude twoards repairing the marriage is hopeless... its a viscious cycle...
YOU have to BREAK the cycle by setting an adult example, doing what needs to be done to save the marriage DESPITE the negative cynicism that he's throwing at you... You can't let HIS hoplessness beat you down...
Hoplessness breeds more of it if you don't combat it... don't expect his hopelessness to go away before you act... and don't pay it any mind, just do what needs to be done as a marital partner and he will follow suit... if he's not addicted to anything