You are the one violating the NAP. I have only grabbed more provinces because you lost them to Ma Arcoscephale. I took care of his pretender, that you couldn't kill, and grabbed his remaining provs, to kill him [as you had no armies able to do so]. I was willing to honor our agreement, but I only got a threatening PM, which made me worry about possible good relationship. I never got a reply on my PM, where I suggested giving you that provs back in exchange for some small reparation for using my armies to kill enemy that was conquering your provs and killed your pretender.
And now you come with stealthy armies, that must have been preparing that attack for many turns. So it looks like you planned to launch that attack from the beginning
