Physical intimacy is what makes a relationship more than just a platonic friendship. Some couples fall into a pattern or habit of letting the physical part of their marriage fall by the wayside. While there is a "normal" drop off within the first few years of marriage, particularly if kids come into the picture, complete loss of this physical aspect of marriage often signals a marital problem that needs to be addressed. Without the physical intimacy that differentiates a romantic partnership from a platonic one, married couples can become more-or-less roommates. If both partners are OK with this type of relationship, it doesn't call for concern. But often, one or both partners become frustrated or hurt by the loss of physical intimacy and sex.