Astrology suggests various influences in your cousin’s marriage, with Sun, Mercury, and Saturn in the 9th house indicating complex beliefs and philosophies affecting the relationship. The presence of Venus and Moon in the 8th house and Mars and Jupiter in the 7th house points to intense emotions and turbulence. However, deciding on divorce should go beyond astrological insights. Given the turbulent relationship with issues like extramarital affairs and substance abuse, your cousin should seek professional counseling to address underlying problems and consult a family lawyer for legal implications. Ultimately, prioritizing mental and physical well-being and reflecting on personal feelings are crucial steps in making an informed decision.