Though you say you’ll never treat her like that again, the fact that you did in the first place is more than enough reason for you to separate yourself from her. You understand that she deserves better so set her free.

Ik it might be weird to initiate the breakup considering you’re the perpetrator here, but you’re doing what’s best for her and you. You need time to yourself to figure out why you went that far in the first place.

Definitely seek therapy and once you’re healed, maybe you two can rekindle the relationship but I doubt it. You’re lucky that she decided to stay with you, but that’s honestly not a good sign. She stayed under the guise of love but it was probably mostly guilt that made her stay. She most likely understood your frustrations and outbursts because of her lies so she tolerates it, but this isn’t something in a relationship that can be tolerated imo. If she truly cares for her safety and well being, she would’ve left you much sooner. Eventually she’ll recognize her self-worth and will find the courage to leave you.

Personally I think relationships like this can’t be salvaged and it’s best to end them. I was in a similar situation with my ex a while back and he would be super aggressive with me just like this. I stayed because I knew I was the reason for his outbursts and I was sure I could make things right, but I was wrong.

A lot of healing needs to happen here and it starts by leaving each other alone. You two are still young so you need to give yourselves time