[ethn]

Immediately, without any context other than what you've provided, I would no longer trust him--you should be included in the loop for any major decision like this. If he has no particularly rare redeeming qualities (or if he does, if you can survive without him), discuss it with the board directly. In my experience it is better to not take chances and to aggressively confront this otherwise later you will regret ignoring duplicitous behavior.