Moon in 5th House synastry determines the emotional and romantic attraction of individuals. Moreover, individuals can be so absorbed in a joint occupation of their own housekeeping that they can live together under one roof without entering into a proper marriage! And it is possible that one of the partners will take over the “parental” functions.
Moon in Fifth House synastry partner may also acquire common children without, again, entering into marital relations. This is because matters of the home, children, family, and well-being are the cornerstone life values of such relationships. Even romanticism and physical attraction are secondary here. If these relationships concern parents and children, then a strong emotional connection is established between them.
Both partners stimulate each other’s creative and artistic imagination in every possible way. They are socially active and constantly strive to seek pleasure in life. For example, they like to cook delicious dishes together.
If Moon is positively aspected, it is quite possible to talk about the possibility of a good business relationship between these partners, especially in the fields of beauty and skincare. The lunar imagination enriches the 5th House personality and stimulates his or her creative abilities, thereby provoking a positive response: the social factor in the “lunar” personality’s life suddenly begins to bloom and prosper.
from F. Sakoyan, L. Ecker
Moon in 5th House Synastry Explained
A Moon in 5th House synastry partner should quickly understand that the main (and sole) task of his/her life is to take care of you. Conversely, if they get confused, they may decide that fate has finally sent them a mother/father figure in your flesh. However, the way your lives unfold will quickly show him or her whose health, comfort and well-being are more important (yours), and who should truly be cared about (you).
In general, the Moon in Fifth House synastry is an extremely unfair and asymmetrical aspect (much like many others); the difference is that here the partner is much more vulnerable than you (except for some extreme cases). The partner will tend to perceive your behavior very emotionally and personally while you consider even their most sincere concerns as mere acting.
This may suit the partner at first, especially if s/he is looking for a parental figure and you approach them as a supportive caretaker. But in this scenario may quickly become tough and turn completely astray from where it seemed to be headed in the beginning. Then a breakup is likely, or at least a conflict in which the partner will suffer greatly, accusing you of insincerity and lamenting for the efforts wasted in vain on you.
A positive version of the Moon in the 5th House synastry is, for example, the wife of an artist, protecting his work-and-life balance with attention and care.
from A. Podvodny