Its nothing to be worried as far as its not causing you pain. Its called onychorrhexis caused by repeated injury to nail, prolong exposure to cold and cold water, nutritional deficiency, anemia or hypothyroidism.  You can try oral biotin along with multivitamin supplements which include iron, vit A, vit  C, niacin and calcium for 6 months.(tab hairbless/tab btn ultra/ tab revilus/tab harvest etc.  You can massage with vit e cream.