This is the house of partnerships, the most important one being marriage. Until this house, the focus was on the individual, with this house, the focus shifts from self to the other. This house is just opposite the ascendant. First house is self and seventh house is partner, together they complement each other and make a whole, like Yin and Yang. So seventh house in astrology represents what you are looking for. Everything related to marriage is governed by this house. Your sense of attraction to opposite sex, desire to have a partner, need to commit, sexual fantasies, passion, possessiveness, and level of understanding are all governed by the position of planets in seventh house.
This house also relates to your ability to have children. Seventh house also relates to problems and disinterest in carnal fulfillment, illnesses of reproductive system, impotence and progeny problems. The reason why you indulge in a partnership is also apparent in the seventh house. Is it for love? Money? Social pressure? Practical reasons? Or to fill the void in your life?
The sense of cooperation and purpose is important to the seventh house. By cooperating and adjusting, we seek to realize our purpose, accomplish something like happiness, success, profit, and satisfaction. All sorts of partnerships come under the domain of seventh house, not just marriage. These include business partnerships, relationship with clients, contracts, negotiations, agreements and so on. The kind of relationship you share with your co-founder is governed by this house, who gets a bigger slice in profit is also ruled by 7th house in Vedic Astrology. Your relationship with everyone you enter into a contract with is also governed by seventh house in horoscope. Whether all these partnerships enrich your lives or cause your downfall is also assessed by the planetary position in the seventh house.
Seventh house also deals with the darker side of our relationships, the partnerships we form. Legal battles, divorce, quarrels, enmity, and fines also fall under the domain of this house. Your reaction to these adversities influence your relationship with the person and on a more global level in mundane astrology, it can lead to wars. In Mundane astrology, seventh house controls matters related to treaties, alliances with other countries, foreign affairs, law, international conflicts, foreign trade etc. Known as the Kalatra Bhava in Vedic Astrology, this house is ruled by Libra sign. Planet Venus is the natural significator of this house that also signifies love, romance and sexuality. It governs several body parts including kidneys and lower back.