Marriage compatibility in astrology explores the harmony between partners by analysing planetary influences at their birth. In Western astrology, based on the Sayana (tropical) zodiac, compatibility is viewed through psychological and emotional lenses rather than rigid fate. The Sayana zodiac system aligns the zodiac with the changing seasons, taking the Sun’s position at the vernal equinox as the starting point of Aries. Unlike the Nirayana (sidereal) zodiac, which is fixed relative to the constellations, the Sayana system emphasizes the Sun's seasonal position, focusing on symbolic meanings, planetary aspects, and house placements rather than the fixed stars.

Key methods include synastry-comparing two charts to assess inter-aspects between Venus, Mars, Moon, and the 7th house ruler-and the posited planet, which merge two natal charts to reveal the relationship's purpose and dynamics. Modern Western astrology incorporates psychological insight, archetypes, and emotional patterns, focusing on self-awareness, mutual understanding, and free will.

Unlike Vedic astrology’s point-based Guna Milan system, the Sayana approach is qualitative. It evaluates communication, emotional resonance, and long-term potential rather than fixed predictions. Relationship challenges are seen as growth opportunities rather than fate-driven problems.

This makes Western astrology particularly valuable in relationship counselling, offering deep insight into shared values, needs, and chemistry. It supports conscious partnership development, highlighting both strengths and areas requiring mutual effort for a lasting and meaningful bond.