I don't think being strong and being in an abusive relationship are mutually exclusive.
An abusive childhood made me strong and independent at an early age. Long before reaching double figures I was resilient in a way many adults aren't.
Throughout my teens I genuinely didn't understand why peers with supportive loving families, who were the victims of bullying let it even bother them, from my perspective at the time it was just weakness to get upset about treatment that was fuck all compared to what I coped with at home. I could only empathise with vulnerable peers.
It was a case of learning the hard way not to give a fuck what anyone else thinks, and not to be dependent on anyone. I remember being in y6 and having the realisation that even though I was clearly a vile child to warrant the abuse, I could either give up and die or get on with it. Finding happiness where I could instead of crumbling was also a fuck you.
Didn't stop me getting into an abusive relationship in my late teens, purely because my sense of what warranted abuse was enOk tirely warped. Stuff that would hurt others went straight over my head. Even the things I did notice I didn't think were abuse I thought were deserved because I was so vile. Being pregnant changed that because I had to protect myself to protect my baby.
There were times after I left I had problems in a practical sense, no amount of mental strength made up for his physical strength or my circumstances. But to this day I don't feel I have that much in common mentally with other dv survivors, because it genuinely didn't leave emotional scars. I don't think that's down to strength per se, more that after my childhood it was trivial.
You could say my strength comes from knowing I don't need the approval or support of anyone else. And the determination that my child will not have her childhood ruined whilst I wallow in self pity about mine.