Many have attempted to achieve unity in groups numbering two or more through creating and adopting a set of shared beliefs. The problem with this approach is that our lives consist of a stream of new experiences which hopefully catalyze growth in what we think, feel, and do. Subsequently, whether as pair or more, the only way to maintain unity is to either continue to grow together or to ignore the growth suggested by new information. The former is difficult, but the only way to achieve true and continuing unity.
As applied to marriage, this principle suggests that the criteria of finding someone who thinks, feels, and does what you do is not ideal, as this will only result in someone who matches who you and they are right now.
A much better metric is to find someone who cares about improvement as much as you do; someone who desires, searches for, and does what is best, and does so based on their own independent rational evaluation of evidence. Under this paradigm, you will build and continue in unity as you share and process the reasons for which you think, feel, and do as you do, no matter what you encounter along the way.
Intimacy in marriage is built as two people discover themselves and the other through successive revelations yielded by joint life experiences. To make peace through holding back part of yourself is to kill the living and best part of what marriage offers, and this is the best case scenario for a partnership based on matching your current beliefs.
To achieve the benefits worth the cost, you have to be who you really are, find a person who does the same, and help each other to become the best you can be.