Midnight - whereabouts are you? You sound like you are in a very similar position to me.
My advice would be to keep your own counsel as far as possible with as many people as possible. The person you have to consider the most beside yourself is your wife and only you know how much of your personal integrity you wish to compromise in order to keep your marriage secure. By that I simply mean I am in the same boat and I know first hand that not everyone can make high impact statements regardless of the consequences.
Beyond your wife and immediate family however my recommendation is to say as little as possible. Anything you do say can be used against you. The less you say means the less they have to process and determine what it means for how they want their relationship with you to develop, For many a "don't ask, don't tell" policy means they can mentally salve their their conscience about contact and keep you out of the "apostate" category.
If you openly admit to being an atheist then at best you are giving people the green light to treat you like a DF'ed person. At worst you are alerting the elder squad to your situation and inviting investigation and malicious judicial treatment. If that doesn't bother you then fair play but if you are looking to keep the peace then the only real option is to keep shtum and avoid controversy where possible.