How Mars in the houses of Relationships and Emotions causes Mangal Dosha. This Dosha hampers married life and causes many issues in relationships. A detailed study of Mangal Dosha from Ascendant and Moon Sign.
7th house is house of highest desire, it called the Kama trikona (The trine of desire). Our deep rooted desires are in 7th house, as it is 4th from 4th house and 10th from 10th house (Concept of Bhavat Bhavam). 7th house is very critical, it is also the maraka bhava (Death inflicting) , as its opposite to Ascendant (Lagna), which means going away.