How does Bhauma Dosha or Kuja Dosha affect a person?
First, although a person may have certain conditions in his chart, that make him Manglik candidate, there are various degrees of Bhauma Dosha. Some configurations indicate strong Dosha (defect), while others are less virulent and some can even be called mild. Since there are only 12 houses and presence of Mars in any 5 of them make one a Manglik, nearly 42% of the population are likely to be Manglik!!
Mars is a wrecker of marriages. The amount of damage Mars can create also depends on other factors like the strength of the 7th House Lord (the ruler of marriage), occupation of good or bad planets in the 7th house or their benefic or malefic aspects, the strength of the planet giving longevity to the spouse amongst other things. A full analysis of your chart will give these details.