Thank you very much for posting the composite charts. As you may know, composite charts are the chart of the relationship itself and so can give insight into how the relationship works as a whole. Composite charts do NOT show issues between the people in the relationship. For this we look at chart synastries to find the easy/challenging energy connections between the two people.
Your 6 year relationship has a strong focus in the 11th house (friends, also rebellion) the "close but not TOO close" house!
With Venus (relationships) there as well, indicating that this was a "friendly" relationship. Also the focus is mostly in the "Universal" houses (houses 9-12), which are the houses "beyond" personal and sociable focuses. This could indicate that the relationship focused on "big" issues, and perhaps therefore never "noticed" the personal and interpersonal challenges developing. In addition, Neptune (spirituality, also confusion, deception, idealization) is conjunct (energy is combined with) Ascendant (self), indicating there may be some idealizing in the relationship. This possibility is increased with Neptune sextile (energy goes easily with) Venus.
Looking at the other chart with your friend, this relationship is also focused in the Universal houses, although there is also a focus on both personal (houses 1-4) and a stronger focus on the sociable (houses 5-8 ), missing in the other chart. This brings in an awareness in the relationship of the relationship itself and of the relationships going on around the relationship. Also in this chart Neptune and Venus do not touch, and Neptune is not conjunct the Ascendant so the relationship is less confusing and idealized. This relationship may be, for these reasons, more "self aware" of what it is and what it is not.