The two pillars of marriage are communication and expectation.
Communication is simple: heart to heart. It means that my mates knows my heart better than I do and I trust them with my heart more than I trust myself. Men love to be heard without a word and women love to be heart-seen. 1 Peter 3:1-6 talks of men being heard without a word. They can be led to God by their wives without a tongue having to move. Women want their heart known in a way that allows them to rest and trust another with their heart.
This is very dangerous. This is hidden, under the radar type of stuff. We all come into relationships expecting certain things. Some of the things we are very aware of while the deeper things haunt us. Usually they are unspoken promises we have made to ourselves from our childhood. They are usually discovered when we encounter a situation that demands danger to the soul. When we don't stay in that condition you can usually see what the issue is. They will say something like this: no one is ever going to make me feel that way again.