I mean this kindly, but part of healing is being honest with yourself and owning your part in this.
I have a daughter that age, they are not stupid. They love and need their mums.
They need them with their shit together, not being emotionally abused by absolutely vile men.
Teens have their own worries, insecurities and stresses. Having a stable, emotionally present mother is their rock and support.
They need this.
Please try and be honest in how this has impacted her. Ask her. Own it. Own how this will have been for her to witness.
I think if you can be brave enough to own it, it will give you strength to never have anything to do with him again, preferably block him, and take a long break from men while you build your boundaries and self respect.
Do you want to wait for the truth when she is in her 20's and she tells you out straight how your choices impacted her?
Or that she chooses to go low contact with you because of it and relationships like this, if it becomes a pattern.
Own it, apologise for it, ask her to be truthful, listen and learn, and I bet you will be a much stronger woman from the experience, hard though it may be.
Wishing you both well.