You have a right to be safe. You deserve to be treated with respect. Abuse is unacceptable. We all experience stress, trauma, anger, and fear but a violent lesbian chooses to use violence to control and get her own way. She uses violence deliberately to weaken your choices to act.
Domestic violence is a crime.
If you feel scared and unsafe in her presence, then something is wrong. You are the best judge of how safe you are. You may not have told anyone about the violence. You may have told friends who have not understood your danger and distress. Acknowledge the pain and grief that the abuse has caused.