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 Sextile Jupiter
A Sun sextile Jupiter aspect like this one gives you a willingness to assist your partner materially and emotionally to succeed. You are likely to have a strong friendship along with your romantic relationship. You will enjoy your partners sense of individuality as well as you will enjoy doing things together and are likely to be very successful where ever you team up. When the Sun person is sextile the Jupiter person, you will find them willing to encourage you on your adventures, as well as join you when you desire company. You will find that you are both lucky for each other.