If Mars is in the 7th house, married life is rather spoiled, regardless of what sign the planet occupies. The person may marry at an early age due to physical attraction. There may be tension, arguments, and fighting within the partnership. The possibility of more than one marriage is very high. The person will have an extremely powerful sex drive, and unless Mars is well aspected may engage in extramarital affairs. Ancient Hindu scriptures declare that the person will be "immoral and indulge in sexual perversions such as kissing the private parts of another". If Mars is badly aspected, homosexuality may result. The sages have also stated that if Mars is with Ketu in the 7th, the person will not mind having intercourse with a woman in menses. The person's spouse may be aggressive, argumentative, very physical, and corrupt or sinful. Mars, more than any other planet, when afflicted in this house, can cause violence or early death to the marriage partner. There is a strong chance that the person will move from his native place and enjoy success in a foreign country. Health is harmed by Mars' aspect on the 1st house. The person may drink alcohol due to the aspect on the 2nd house. Because Mars gains strength in an angular house, the significations of Mars are strong. Hence the person may own property or buildings and have many prosperous younger brothers and sisters. He may also be rash or aggressive. There will be difficulties with business partnerships. Mars in the 7th house is an indication of Kujadosha, or Mars affliction, where married life and domestic harmony is spoiled unless the person marries another with a Kujadosha horoscope. The 7th house Kujadosha is nullified only if Mars is in Capricorn or Pisces.

UCHCHA and SWAKSHETRA (exalted and own house). If Mars is in Capricorn, Aries, or Scorpio in the 7th house, married life is still harmed, and the person may marry more than once. However, the spouse is of much better quality and may be wealthy, powerful, prosperous, and special. The best placement for Mars is Capricorn, and because Kujadosha is nullified in that sign, there is greater peace in the domestic sphere. The person will likely travel to foreign countries and enjoy much success there.

NEECHA (fallen). If Mars is in Cancer in the 7th house, married life is very difficult. The partner may be gross, mean, insensitive, or violent. He or she may also be very physical and sexual. The spouse may lead a difficult life or die early. The person with this placement is very passionate and sexual. Marriage may be filled with fighting and will likely end in divorce.

Source: «Ancient Hindu Astrology for the Modern Western Astrologer» by James Braha