I realize that your pot use isn't a new thing, but the whole having a baby, kinda is... Have you had a calm discussion about this? Has she said what exactly about it makes her want you to stop? Maybe she's going into over protective mode, and this is part of her child-proofing the home strategy. Or maybe this does have to do with the legal side of things.. Maybe she wants to bring her child up in a household sans illegal activities.

I also don't really think she's telling you to "be perfect or move out." I understand that that is how you are feeling and don't want to invalidate that, but I'm wondering if it's an accurate portrayal of the situation?

I think the first thing you should do is sit down and have an honest, calm discussion with your wife on why this has suddenly changed. Try not to be defensive, or say something to put her on the defensive. Just say something like, "I want to understand what has changed in your mind and if we can work on a compromise." Just remember... she does have a lot of hormones going coursing through her body right now....

Good luck