Absolutely sounds like trauma bonding to me too. It's incredibly unhealthy and the relationship is doing more harm than good. It's physically abusive, emotionally manipulative (in many ways), and emotionally abusive. By triggering each other's trauma responses and the fact it's escalated to physical contact and suicidal ideation, it's imperative both seek counseling to work on healing and deal with their anger issues. For both their safety, they should separate to avoid adding more trauma to an already horrible situation