The Sun is the source of all energies. These energies stimulate the activities of the houses occupied by the transiting Sun and reinforce or weaken the planetary effects, depending on the Sun's aspect to the natal planet. When the Sun transits an inner planet, it may trigger a dormant aspect between that inner planet and a slower moving outer planet. If a planet is being transited by another planet when it is being transited by the Sun, the effect of the transit is strengthened.
Sun Inconjunct Mars
A sun inconjunct Mars aspect indicates a real difference in your desire for and capacity for activities. When one is ready to start the other isn't. When the other gets going, the Sun is ready to stop. Romantically and domestically this has the possibility of making you time together seem exhausting because one is always feeling pushed and one feels that so much energy has to be expended just to get things started that it would be easier to do things by themselves. This aspect works this way no matter which partner has the Sun inconjunct the partners Mars.