I can relate. It will be great to work with your IC on this.
My IC tells me that if we don't work on our past issues, we are doomed to repeat them. Working on this issue now, will be a huge step for you IMO.
My IC always asks me about my dreams, and what I can relate to them. I don't remember many of them, but when I can, I write them down, and discuss at my next IC session. Do you discuss your dreams with your IC?
In my case, not only did I figure out that I had abandonment issues, but also issues of trust. I had trust issues with my FOO, and also with relationships as a young adult, and even within my marriage. Some of it was based on me projecting my own issues of lying and leading a second hidden life from everyone in my life.
Good luck with this. I have found that these types of FOO really are at the core of the unhealthy coping skills that lead me to where I am.