1) Deen choked Angel in her sleep
2) When things didn’t go well on set, he took his anger out on Angel
3) At parties he was charming, but in private he was a “monster”
4) He feared being known by his true identity
5) He treated women like objects despite being considered a feminist
6) He nearly drowned her in a sink
7) He was controlling of every aspect of their relationship, especially sex
More (very graphic) details at the second source.