Yep know what you mean. My son can act just like his Dad. I just tell him not to do it. My ex has narcisistic personality traits. I am afraid my son may treat people the way his Dad does.
Here's an example: my son was walking around the house brushing his teeth at the same time-this is something the ex did-he would walk into the living room and stand there brushing his teeth and watching the t.v. I told my son-oh no you are not doing that at my house. Your father did that and I will not have you doing that here.
There will be things that come up that will remind you directly of a behavior you ex had.
When my brother got older his voice sounded just like my Dad's. I can remember asking my Mom if that was hard on her. They were divorced and it was weird to hear the voice but have it coming out of my brother-seemed like my father was there talking.
-------------------- Message for my ex "I think you know by now, I'm not the person I used to be"