One of the major things that I have learned on my healing journey is to take 100% responsibility for anything that happens in my life. I know this sounds a little crazy at first, however, I now know that it is the only way for my life to really transform.
I know this other person was irresponsible and had some poor behaviors; however, I wonder what type of theme she is reflecting for you. Do you often find yourself angry because you have done things you didn't want to? Do you seem to attract people into your life that are demanding and don't return the support you give them? Do you have beliefs about being kind, doing for others, not saying no that tend to push you into not having boundaries? Does the term boundaries make you feel confused, frustrated, or angry?
Focusing on the other person and their behavior will never actually change what is happening for you. It would benefit you more to learn about your own patterns of behavior, your own thought processes, and to recognize how you ignore your feelings.
I studied in depth about boundaries and found that I had never had permission to have them; in fact, I was punished for ever even trying to have them. As a result, I brought people into my life that walked all over me and found myself dealing with a tremendous amount of anger--or depression when I was stuffing the anger.
Use this experience to support yourself in looking deeper into your own reactions and finding the places to heal that will utlimately help you to not even attract people that treat you like this any more. We really do teach others how to treat us. We can only change this by changing our own belief systems and owning our own feelings and behaviors.
This isn't an easy process, however, it is soooo worth it. While you do this process it will be extremely important to be gentle with yourself--to resource you pain, anger, frustration, and confusion through journaling, asking for help, tons of self-care, and learning all you can about boundaries, saying no, and how to communicate openly, directly, and clearly. Best Wishes, T.