I am just guessing that maybe the driver of the other car thought that your husband slowed down or driving slow to let him go.

It could be that your husband was driving too slow because of the humbs and because you are pregnant, and the driver see you but knows that he can easily do it and turn with no accident because you are driving extremely slow, or thought that this slow motion or slowing down this much is a sign for him to turn.

anyway, it is no wonder that you or your husband will face such drivers every single day. Driving is an Art. It is not only knowing how to drive and following the rules, but how to be aware of other drivers who just got thier new license and practising thier driving or those teenager drivers, or drunk drivers...etc. Simply, care about following the rules and be aware of other drivers all the time because it will happen always.