There is a book by Karen Landsman, Kathleen Rupertus, and Cherry Pedrick called Loving Someone with OCD (2005) that addresses this question in great detail.
The book discusses many topics, from intimacy to creating contracts about decreasing reassurance-seeking.
It contains many different charts and exercises for spouses to do together, such as creating a log of accommodating behaviors to decrease (behaviors that your spouse may do to assist you with your OCD, such as helping you with your rituals or giving you reassurance when you seek it), setting up a family contract about how you and your spouse will handle the OCD together, and even how you can, as a couple, find a therapist or a support group.
The goal of a marriage is to be able to work together. Although having OCD may make this more difficult, it is not impossible.
It takes effort, but couples can devise a mutually beneficial plan that will address their emotional, physical, and mental health needs.