I've thought about this some more, and wanted to write one more thing. Your composite chart is basically the same as your natals, meaning relationship is a simple extension, feel is familiar and that is what can keep people together. But, in my opinion, relationships should
be complementary, meaning getting from someone something you are not quite familiar with, as a means to grow, primarly.
To be able to see other, and not just another 'self'. As much as two of you seem different, same positions of planets, same aspects, could bring little growth, if any. Maybe it is good for now, for in other we can see ourselves more clearly, so as a way to get to know yourself, it can be good. But on a negative side, it gives lots of opportunity for projection - everything unacceptable in yourself will become very
visible in other.
This is very debatable subject and I am not saying I am right here by any means, just my two cents