I (M28) feel betrayed by my girlfriend (F31)

Quick context. A few years ago I was gaming with someone online. I flirted a bit. Then I asked her age. She said 17. I was 26. I ended the chat right away and cut contact.

Later, after I broke up with my partner at the time (F, same age as me), that 17 year old messaged F with lies and altered screenshots. She made it look like I kept going after her even when she told me her age. F believed it then. A year later, when me and F reconnected, she confronted me about this situation about 3 months into us seriously dating again. I still had the real screenshots and full conversation with the 17 year old and showed her. She realized the girl lied (for whatever reason it’s none of my business).

Now to the part that shocked me. I asked F something that’s been bothering me for days now: If she really thought I was fine with being with a 17 year old, why was she still willing and okay to be in a relationship with me again?

Her answer stunned me. She said she overlooked it because I had many good traits and because she knew I had been severely abused as a kid sexually and physically. She said maybe because of that I was some kind of sicko who was okay with dating someone under age.

My trauma has nothing to do with this topic. I shared it with her because I trusted her. F was the only person in this world I could trust, she was the first person I opened up to. She is also the only person that knows about my past asides from my therapist. Hearing her use it to explain why she would tolerate something she believed was wrong made me feel sick. It felt like she turned something painful and private into part of her reasoning.

I feel so betrayed and so naked in a way and im very confused and hurt and I genuinely don’t know how to feel. Ive been in therapy for years to get over my past and now it feels like that progress is all gone.

Am i overreacting? Or is her reasoning correct ?