Basically our sticking point is smacking: I refuse to, DH is agreeing for now but still threatens it. He also smacks toys as part of play ('naughty bear, smack his bottom' type stuff).
DS is just 2 and I know that for discipline to be effective DH and I need to have a unified and consistent approach, but I can't get DH to see that smacking toys is undermining the no smacking message, or even to agree not to smack (yesterday he said 'I've just smacked him because he bit me'). 
What would you do? DH is a stubborn bugger and I stand little chance of convincing him, but I don't want DS to get mixed messages, or for DH's approach to undermine mine...
Ideas / thoughts anyone...?