The most difficult area in any relationship and yet the most important is spiritual intimacy. This is because our relationship with God affects everything else we do.
It is true everyone must take personal responsibility with their walk with God, however as couples, we share the walk. In so doing we encourage each other and build intimacy.
Spiritual intimacy affects all other aspects of marriage/ relationship (emotional , intellectual &physical) just like our relationship with God affects all other aspects of our lives.
It is Important to note that the closer a husband/wife is to God, the more they grow closer/Intimate with their spouse in every other aspect.
1Cor 3:11 No one can lay any foundation other than the one we already have-Jesus Christ.