Actually, it’s your boundaries that are causing the repeated failing or abusive relationships. By being too aggressive or passive, you attract others who compliment your lack of effective boundaries. You are essentially putting an advertisement for abuse out into the world.
Establishing healthy boundaries means that you determine the rules regarding how your interactions with the world and others. You demand respect and vow to respect others in return. Having healthy boundaries means that you do not allow the world or others to drain you of what you need to survive or function healthfully.