Mars in 1st House synastry spreads and reinforces your perception of your partner, and unless he or she is your implacable enemy, your attitude towards their activity is likely to be ambivalent. Generally speaking, it can easily “turn you on”, exacerbate personal problems and cause acute personal reactions, and here the interpretation depends largely on the aspects and level of development of your first home.
If a female Mars gets to the first house of a man’s horoscope, the man can ridiculously react to any female activity, perceiving it as a humiliation of his personality. However, a lot depends on how serious he is about himself and what planetary accent corresponds to his male identity. If it is a feminine man with a lunar male identity, that is, feeling a connection with his sex in moments of women’s care, then such a synastry may not threaten his personal dignity (“I am a man for those women who appreciate me and care for me, and the rest are bad feminists“).
On the contrary, for a man of the masculine type, with a Martian or Sun-like male identity, tuned to battle for and win over a woman, Mars in 1st House synastry can be very dangerous, especially if he has the inferiority complex, because in battles with a partner he runs a great risk of aggravating it. However, working to improve the aspect of Mars in 1st House synastry gives him an opportunity to increase his self-confidence (at a low level with a harmonious First House, the aspect will give him a strong temptation of bragging).
If the male Mars gets into the First House of the female horoscope, a man will be relatively easy to suppress the female personality, but only on the surface. The woman, having grown accustomed to the situation, can learn to manage the energy of his partner: a joyful smile or a mean look can have a surprisingly strong impact on him. If the man has the Martian male identification, the woman can destroy or resurrect the man, and her flirting with other men can easily make him overreact.
from A. Podvodny
Mars in 1st House Synastry Explaination
The “Martian” personality exerts a powerful energetic influence on the personality of the “first house”, actively stimulating it to action. The person of the “First House” also does not want to remain passive in this process and stimulates the “Martian” personality. Whether the relationship is constructive or destructive depends on the maturity of individuals and on the characteristics of the aspects of Mars in comparison.
Under Mars in 1st House synastry, there is often a healthy competition in the professional and social spheres associated with attempts to satisfy ambitions. Between partners of different sexes, romantic relationships based on strong physical attraction can also arise.