I cheated on my wife during third trimester. It was random but i did it twice. Its eating me up! Keeping mum seems like my best option...any thoughts?

This is the worse decision you have made, to spoil your own marriage life. You should be honest to your wife and face the consequences from your acts. If your wife is willing to forgive you, never ever do it again. If your wife is not forgiving you, that's your punishment for being unfaithful. If you keep it from your wife, one day your wife will find out too, and I believe the consequences will be even greater.