Don't focus on how other people treat you. Focus on how you treat yourself. If you are in an abusive elationship, for example, don't focus on the abuser's behavior. Look instead at your own. Ask yourself if deciding to be with an abusive person is a nice way to treat yourself.
Be responsible for loving and taking care of yourself. Don't try to give this responsibility to anyone else.
Your assignment is a simple one. Love yourself right now! If you forget, just remember your assignment and start practicing. Tell yourself "I am responsible for loving myself in this moment. If I don't love myself, no one else will. The love of others can reach me only if I am loving myself."
If you are one-pointed in this practice, things will improve. You will stop betraying yourself. And when your self betrayal comes to an end, it will no longer be so easy for others to abuse or betray you.