Growing up in the dysfunction that was your childhood, there is just a lot of pain inherent in that situation. Any child has some very basic needs, and when those needs aren't met by the people who should be meeting them, the child is going to experience a lot of inner turmoil and emotions that they don't have the capability to deal with. So they look for ways to cope. They model the behavior of those around them. They find ways to minimize the pain and hurt of not being loved in a healthy way.
This "player" persona that you created was a way for you to get your needs met IMO. Once you met your BS, it would have been nice if things changed for you in how you dealt with life, but it didn't. You probably knew your BS was different, and you knew that you should be doing things differently, but it never worked in the past, so the old behaviors won out, because that was what kept you safe back when you were a kid.
That is what I mean by covering for the fear. I believe that most people have a scared little kid inside of them that they "know" is there, but that they protect by being whoever they present themselves to be outwardly. It isn't a matter of people needing to tell everyone their life story the first time they meet someone. It's just a matter of each of us recognizing that scared child inside of us. For me, I have a specific image of me as an eight year old boy standing in the front lawn of the house I grew up in. All that little 8-yo me wanted was to feel like I was taken care of and made to feel safe. For whatever reason, I didn't feel that way when I was growing up, even though I had a very "normal" upbringing. Even years out, I don't really know why I feel that way, but the fact that I've recognized that little scared kid inside of me, it has helped me to change who I am and how I trust people. I still put myself out there and find myself disappointed often, but I've changed how I deal with that rather than using my coping mechanisms to stuff it down and not deal with it.
So, Strawda, this may or may not be the situation for you, but it sounds like you had it rough as a kid, and that maybe you've never really dealt with it at the level that you need to in order to make some big changes in your life. Based on your BS's posts, I'm betting that she is ready and willing, and has been all along, to be there for you in your own healing process. You have to learn to trust that she is in this because she does love you. It sounds like that is something new for you.
Like I said, this may or may not be the case for you. It's just what I read in your situation.