Saturn in 1st House synastry can make you think that your partner was sent to you by a prison guard. He or she seems to be able to give you only the feeling of duty, and they do it to a cruel extreme.
You will perceive all of your partner’s manifestations through the prism of brutality, attributing it to your partner and not noticing that in many ways you provoke it yourself. Indeed, in their presence, you immediately become serious, strict and responsible: to yourself, as well as to your partner. However, this does not go too deep, usually dissolving soon after you part. And it’s very hard for you to realize how serious your partner takes your relationship (especially your personal reactions), how often you hurt him or her down to the bottom of their soul.
Your partner needs you to behave in a very definite way, or rather, to keep your personal reactions within some of his established limits. Yet it’s hard for you to understand this and even harder to learn to comply with it, although moving in this direction would do you a lot of good.
With Saturn in 1st House synastry your partner can teach you personal modesty and depth of your own personality, and you can teach them so much that they would be surprised to know how much they owe you as to an indirect source of self-discipline and humility. In general, Saturn in 1st House synastry is difficult, but in marriage it can be very useful, for example, if you have a weak Saturn: then some of its functions will be taken on by your partner’s Saturn, but you should go as far as possible to meet his requirements of discipline, seriousness, etc.
from A. Podvodny
Saturn in 1st House Synastry Explained
Under Saturn in 1st House synastry, relations are formed and characterized by the seriousness of the parties’ intentions. The “Saturnine” personality tries to discipline and hold within the acceptable framework the potential of self-expression of the “First House” person, which, given the favorable and positive aspect, yields tangible positive results expressed in the development of the “First House” personality of perspicacious foresight in constructive life.
Given Saturn’s negativity, the personality of the First House will clearly feel pressure from the Saturnine one who considers the person of the First House to be impulsive, eccentric and immature in moral terms. With a tad of positivity and optimism, however, partners can effectively collaborate in business, financial and professional activities. They are, as a rule, good friends and socially active members of society.