Many times couples plan how they will get to the US. One of them will marry a USC under false pretence and then divorce the USC shortly afterwards. Then they will stage a plan to marry their true sweetheart and apply to bring that person to the US. This is a well known strategy to the immigration officers.
Unfortunately, I think your case seems like one of those to them. Things they will probably check is how your husband came about his CR1. Did he have any children with his ex-wife. Why did he divorce his ex-wife? How soon did he marry you after the divorce? How long did you know each other before you got married? Are you both from the same country, same town? and so on.
Even if you have a child with him, it may even raise more concerns if he did not have a child with his ex-wife.
So you have go be patient for them to check all this. While your marriage may be genuine and authentic, the question could be - was his past marriage authentic? That is what I feel the immigrations is investigating and that is why I feel they didn't ask you for anything because they believe your marriage is genuine but are not sure about your husband's past married. I will not be surprised if he is asked to be interviewed.
If both his marriages have been genuine and authentic then you probably have nothing to worry about - just wait and all will turn out to be fine.