Composite Sun in the twelfth house is a significant position, but it presents challenges that many people find difficult to deal with.
It indicates that through this relationship both of you will encounter aspects of your inner selves that you would normally keep hidden from yourselves as well as from others.
The most difficult result of this Sun placement is that it may make the relationship self- defeating for both of you, particularly if you are not completely honest with each other. Unless you disclose all secrets, they will cause one or both of you to behave in a way that will undermine not only the relationship but your own self-esteem as well.
In any personal relationship, this placement demands that you thoroughly search your innermost selves to understand how previously hidden psychological traits are operating within the relationship. This encounter will make each of you grow as individuals, and the growth it can bring about is more important than your survival as a couple.