Relationship is surely the mirror in which you discover yourself.
Understanding others' challenges, struggles and abilities can help us appreciate and understand our own. Often we project our issues onto the mirror of our partner.
No system, however can reach into a couple's private inner sanctuary; only they can know and appreciate the internal dynamics of their relationship; only they can experience the difficulties and the lessons. The innermost thoughts, feelings and struggles of others are theirs alone to see and theirs to work out in their own way.
As we come to appreciate the dynamics of our relationship we turn it into a powerful means of insight, awareness and personal growth. Relationships serve mutual needs. In the positive the bring joy; in the negative they bring lessons that cant be ignored for long.
In the end, I think compassion & deeper emphatic bond will result in increased good-will, mutual support, loving demands, good humour and improved communication; just to name a few of what relationship tends to be.
All human life has its seasons and cycles, and no one's personal chaos can be permanent. It seems essential, in relationships that we concentrate only on what is most significant and important.