"Bragging"

Im still in very early recovery..still trying to maintain a NC policy but let myself down 2 days ago when replied to his email. DAMN!! Anyway 2 days NC is better than none but still whirling thoughts in my head. Was wondering if this is a common trait with N's? In the early days of our relationship, getting to know each other I regaled some stories about other ex partners. Nothing too explicit nor looking to stir the green eyed monster..just mainly silly stories. He could rage about all his ex crazies and looking back he was almost drawing out stories from me. These stories were again and again used against me...him teliong me that Im always "bragging" about my sexual prowess and using other stories to "remind" me that Im such a f*k up when it comes to relationships. "After all...look at what happened with...so and so..." and on and on always using this against me to more often than not explain his sudden change in mood and totally out of the blue. He would sometimes even start our evening by saying "I hope your not gonna start your bragging tonite?" I learned very early not to talk about certain things in fact looking back best not to talk about anything to do with me that way he couldnt have a go or blame me for his anger/upset even though he usually did find a way to blame me. His mood would change so swiftly I never seen it coming most times. Why do they suddenly change in an instant?. Is it something we do or do not do? This is the thing which really turns my brain into a tasmanian devil..trying to work this out. Sorry this post bit all over the place..but welcome to my head!..lol
Lxx