From Susanna Barlow's website
Creating and Maintaining Healthy Boundaries
What is a boundary? A boundary is a clear communication that respects yourself and others based on your values, what matters most to you and your personal rules and limitations. A boundary is like an invisible line in the sand between two people, that creates respect. Boundaries are not created for others, in regard to you. In other words, boundaries do not tell others how they can and cannot treat you. They let you know what your limits and rules are, for how you behave toward yourself and others. The boundary is for you: for your protection and self care. A boundary defines where your personal power is, what you have control over and it clarifies what you cannot change or affect. To create and maintain healthy boundaries you will need to first decide why you want boundaries in the first place."