The older I get and the more situations in life that come my way, the more I realize that I have really bad boundaries. I've read the book Boundaries. I'm currently reading Take Back Your Life. Both help to recognize the issue and develop healthy relational habits, but after 18 years of growing up with horrible boundaries and with some abuse from adults, I know some habits I have are wrong, it's just hard to change them. It's all I know. It feels wrong and bad because it hurts me and it hurts others. However, I don't know how to be any other way. I'm learning to stand up for myself in healthy ways, learning to take care of myself, learning to have boundaries. It's not just about keeping unhealthy stuff out, it's about letting the right stuff in. Instead of developing healthy boundaries, I tend to have no boundaries with the wrong people, get hurt, then cut them out. Then, cut all people out, whether healthy or not and live on an island. Then, get sick of being alone and isolated and let the wrong people in. Repeat cycle.
Here's a good article from blogger and author Elizabeth Esther. She has a similar (though much more severe) background to mine and her insights are spot on.