Its actually quite normal to test limits and even rebel in a relationship regardless of if the submissive partner is a survivor of abuse.
Survivors however do have triggers they have to deal with that make their situations singulary dificult at times, we often cannot be expected to preform the same way and things have to go at a different pace.
Please remeber its not your fault if a trigger is activated, nor is it nessesarally the dominants fualt.
Eaither way a safe word should not be relied upon as a crutch to relieve responsibility from the dominant, they are still responsible for ending play if he thinks your having an episode or if things become unsafe in any way, it is especially hard to stay mindful for survivors in bdsm situations as the submissive partner, we have a tendency to get lost in cognitive disasociations with a lot less stimuli that can sometimes cuase us to become trapped as it were in a state of mind where utterance of a safe word isnt possible for us.
Comunication is paramount, the more your dominant knows you, the better he will be able to recognize when this is happening to you.
I highly reccomend you both have a real life kink friendly therapist to work with together too who understands bdsm from first hand experience as well as what it is like to be a survivor.
We discuss a lot of this in the the following thread at different times, including how survivors have some unique requirments for successful intergration of bdsm into their life and how a dominant should be prepared to alter their own views conserning many things conserning play with survivors depending on their individual circumstances.
http://www.bdsmlibrary.com/forums/sh...or-submissives