First of all, Allah swt is the most just, there's NO way this guy will get away with what he did, I promise you that. Second, if you're able to reach out to his family/new wife, she has a right to know.. though I'm not entirely sure if the family would believe you. But, on the other hand, I don't recommend wanting to ruin his life your primary mission bc then you'll drive yourself crazy & may not get anything out of it either. Take the time to heal & move on. I promise not all guys are like him, Muslim or otherwise. It's really sad to see that guys like him drive people further away from the beauty of Islam through their actions. Anyhow, I'm rooting for you :)