Saturn aspects in synastry are notoriously difficult to handle. Saturn represents depression, restriction, fear of rejection, distancing, as well as commitment. Saturn aspects are certainly binding, but come with many problems. Here are some descriptions of how hard aspects (i.e. the conjunction, square and opposition) from one person's Saturn to another's Sun, Moon, Mercury, Venus and Mars manifest in synastry.
Saturn Square Midheaven
This is not favorable for mutual harmony in professional or personal relationships. There can be coldness or lack of understanding in regards to family affairs or personal feelings. There can be problems between the interests of one person and the responsibilities of the other. Be careful to not let family and professional life conflict too much and a midway must be found in order to sustain this relationship.