Even when two persons' signs don't match, they can have a long time relationship. Often Venus is making a sweet aspect between the charts and than everything looks sweet, nice and attractive. Seal and Heidi Klum never had matching charts. They were together long enough to become parents. Venus quatronovile (160d) Venus was of great help and so was his Mars biquintile her Mars. They had a good time, but now it is over. Here is the chart of the day of birth of Seal. The transits (the positions outside the circle) are Heidi's.
His Sun in Pisces, hers in Gemini
Those signs - and life styles - don’t match. Who is the boss? Who is the one getting attention?
Her Moon in Gemini and his in Sagittarius or Capriocorn. No match. They have to make compromises to live in the same room.
The signs of their Mercury are Aquarius and Gemini. The Mercury’s don’t make a nasty aspect, so they seem to be able to communicate.
Venus quatronovile Venus is great. They enjoy each other’s presence and love each other. Such an aspect helps to keep the relationship going for a long time, even if there is no match.
Mars biquintile Mars:; creative cooperation! They created 3 children!
Passion is OK and so is communication, but they have a different life style and different habits. But they also have a mutual Pluto-Sun synastry. Pluto is for intensity and intensity makes it hard when you are basically different.