Well that just sucks now doesn't it? I'm sorry to hear you are going through this. Unfortunately its very common...
Yup, you have been cheated on again. She broke her promise and broke the boundaries you set. That sucks for everyone.
Cheating causes huge issues for people. Those issues get right at the core of a persons feelings of worth. To me there is probably nothing worse in a relationship than cheating. The results quite often lasts a life time and nothing is the same again. Sure, you can move on, even love again, or continue to love the same person, but the trust is never there to its fullest again. Something very precious and innocent dies.
I have abandonment issues also and they have only been kept at bay by my realization that I am alone in the world and that I can only rely on myself. I forget that regularly and have to pull back from most people. Its been a life long struggle and I have worked hard at it... still do. The loves I have I trust entirely right now in my life and I have decided to allow myself that... I have been truly blessed that they are trustworthy and have proven that. I still feel incredibly vulnerable though and its quite often very uncomfortable.
So what to do now. Well, she has some work to do. She clocked out. That is a huge thing. I think looking at that would be the first place for her to start. She seems to think that might be an excuse and it isn't. There is no excuse for breaking a boundary... if she knew this was coming then she should of mentioned it long before hand, gone over the boundaries and made sure you were okay. If you weren't then she should of not done it. That is how trust is built. Not by fucking around behind your back and telling you she forgot what the boundaries were...
I think now is the time to cut right back and not engage in anything for a very long time so as to build trust. If I were her I would put myself in some very tempting situations and NOT do anything so as to prove that she can do it; not only to you, but to herself also... its not okay to think that whatever she wants is what shall be. It's whatever you have agreed to that should be. I struggle with that too, I think most people do... its just practice and figuring out how to NOT clock out when someone tempts me.
The joy of holding an agreement, being respectful, having integrity and being considerate far outweighs the moments of sex that are long forgotten after you cum and realize you are in deep shit. It's just not worth it until the moment is made out of everyone being on board... this I know from experience.
There are some people that are free agents in poly and do as they wish. That is fine and suits the situation... for couples opening up it is much different... just saying as some people who read this might have a different idea about openness in poly.
As for you and where you are WTF (nice name
), I think now is the time to do some huge work on your issues with this. You have become damaged I would imagine by now and you really have little reason to trust, nor should you. Doing some work around your issues will help build you up to realizing that you are independent from her and anyone else you date.
You have no control over others, but you do have control over your own thoughts and feelings and they are totally valid. At some point you might be able to trust her enough to be okay with her going out into the dating world and know that you will be okay because you have yourself and your own stuff going on. That sounds like it might be a long way off; thanks to her and the other women that have cheated on you. I would love to say that by letting her go do her thing she won't perseverate on having sex with others but I think its too early for that... she has a lot of sucking up to do and a lot to prove.