I cannot see the dream of theft you are referring to? Perhaps you need to post this again, sorry.
To dream of nipples can be symbolic of a need for nourishing, comfort or love. This can also indicate a feeling of indebtedness, or an over dependence on maternal love or approval.
To dream of the cutting of a part of the body, as in the nipples in your dream, can symbolise a need to pass from one phase in life to another, or from a specific set of goals or values, to a new one, as in changing or revised priorities in your life now, as compared to previously, or a development or advancement, such as in personal development or enlightenment. In a woman, this can symbolise a focus on hidden strengths, or a resentment at being held back. Being cut in half, can symbolise a separation, such as of different parts of yourself.
The act of swimming in particular can be interpreted in terms of a being indicative of a receptiveness to to your unconscious, to nurturing qualities, to nature or a higher power.
The conflict in the dream can be literal, as representing waking life, or can be symbolic of a conflict within yourself, as in the conflict between what you feel you should do, and what you actually want to do, and may mean your natural instincts or desires require to be listened to more carefully.