Impress him. Surprise him. Cheat not. Hit not. In simpler terms, these are the most important pieces of advice on keeping a relationship. But sometimes, no matter how strictly you follow these commandments, relationships still die. Some of natural death. Why? Because we tend to overlook simpler but not any less significant things we have to remember when we are the other half of a couple. 9. When you make mistakes, say sorry. Your heart should be bigger than your ego. Pride will get your relationship nowhere. When you suddenly threw tantrums in the middle of your seventh monthsary dinner…