Pluto is the planet of death and regeneration. In a composite chart it represents those energies that cause a relationship to go through periods of heavy change. Its action is absolutely essential to prevent the stagnation that occurs when an old way of life has outlived its purpose.
Pluto operates with such tremendous power that it may be divorced from its "death and regeneration" aspect and be experienced purely as power. The power results from the inevitability of Pluto's transforming quality.
In a relationship, Pluto is very often experienced as power conflicts between the two of you. In a sexual relationship it also gives special power and impact to your emotions and makes every happening very dramatic and important.
The house position of Pluto indicates the area of the relationship in which there is most likely to be a conflict of power, either between the two of you or with the outside world. It also indicates which area of the relationship is most likely to be transformed through your being together and as a result which area is most likely to produce crises.
The aspects to Pluto indicate whether this energy will be experienced as difficult or easy and what other energy patterns it will be linked with.