Sun in 10th House synastry relationships are fairly common in business and politics. The more active “Solar” personality has its most direct stimulating effect on the less energetic Tenth House person, making him or her more ambitious and career-oriented, and less hung up on false fears, limitations, and indecision. In politics, this synastry is largely determined by comparative combinations in each natal chart, so these individuals may well turn out to be not only comrades-in-arms, but also rivals, and even sworn enemies.
from F. Sakoyan, L. Ecker
Sun in 10th House Synastry Explained
Sun in 10th House synastry: here (and in general when interpreting the synastric aspects of the Tenth House), it is important to take into account each partner’s age, social, spiritual and energetic position. If they are roughly the same, then this partner may seek friendly advice from you: without attaching particular importance to what you say. However, you are likely to take this more seriously. Most likely, you will clearly see your partner’s situation, at least on its surface layer; but when you suggest a particular course of action you will still subconsciously focus on your own ethics and ideas about the world. So, as psychologists would say, you are not being objective because you try to solve your problems on someone else’s life material.
The karmic meaning of Sun in Tenth House synastry (for you) is that the partner, by his very existence, confronts you with the need for practical choices, although it may seem that both of you are dealing with his problems. If the partner is significantly older than you or is higher on the social ladder, he may be tempted to teach you how to live by giving a lot of practical advice (as in: “You should major in physics, not psychology, because you better engage in a serious business instead of tricking losers…”) Such advice will either cause a vehement protest inside you, or you will be inclined to obey his will, albeit temporarly, until your power grows enough to engage in a battle for independence: much like a teenage girl would fight her dogmatic mother who regulates her daughter’s life to the point of absurdity.
If your Sun in 10th House synastry partner is inclined to perceive you as an advisor, senior friend or practical spiritual teacher, then you will have a dangerous temptation to control her will and initiatives – which ends up stopping them as she slavishly succumbs to you, which may be your goal at a low level of spiritual evolution. Working on this, though, will give her a true spiritual mentor, and you – an endless flurry of specific problems with ethical implications, none of which can be solved easily.
from A. Podvodny