Sex drive often referred to as libido is a natural urge of any healthy person. And in fact, it is Nature’s guarantee of the survival of the species.

Natural proclivities
Sexuality in a civilized society is subject to bounds of a generally accepted moral code and there are laws governing sexual behaviour as well. Meanwhile, human sexual proclivities may differ from person to person and it is a given that sexual proclivities of certain individuals lead them to go beyond the generally accepted natural norms in sexual behaviour to gratify their desires.  The sex life of a person normally begins with marriage which is looked on as a sacred institution and a person’s innate sexual orientation becomes an important determinant of the success or the failure of his or her married life.

7th House provides the clue 
In Predictive Astrology, the 7th House in the Natal Chart of an individual provides the clue to his or her sexual proclivities which could make a decisive impact on his or her sex life within or outside the wedlock. 
Sages in ancient India in their classical works have highlighted certain planetary combinations centered on the 7th house that point to the sexual proclivities of an individual. Now let us get familiar with some such combinations.
If the lords of the 2nd and 6th Houses have evil conjunctions when the 7th lord is associated with the Ascendant lord, the native would be of loose moral character.

One would become immoral in his early years if the 7th lord joins Rahu or Ketu and comes under the aspect of Mars or Saturn while Venus is weakly placed. 

If a weak Moon joins a malefic in the 7th House, the person becomes certainly immoral.

Venus in the 7th House makes the person extremely passionate.

Mercury with Venus in the 7th House makes the native have sexual relations with many of the opposite sex.
Mars with Mercury and Venus in the 7th House with no beneficial aspects would render the person extremely passionate and resort to unnatural means for gratification.

If the Moon is debilitated in the 7th House, the native would sexually abuse maids under his command.
If Mars is in the 7th House with no beneficial aspects, the native would stoop to sexually abusing unmatured girls. 
Should Venus be in a Navamsa of Mars or in a sign owned by Mars or is aspected by Mars or conjunct with Mars, the native, while in liaison with a female would resort to other physical means than the normal intercourse to gratify his desires.

In a female horoscope, if the Ascendant or the Moon falls in the Thrimsamsa (30th Division of a sign) of Aries or Scorpio and if Mars is afflicted, the girl would become a prostitute before puberty. If the Ascendant falls in the Thrimsamsa of Venus, she would become adulterous.

In a female horoscope,if Venus and Saturn exchange their Navamsa, the girl would become extremely passionate and would gratify her desires by unnatural means.