Chances are good that communication is at the heart of the problem.
Here are three things to consider that will help you restore a healthy relationship. They are not difficult -- but neither are they easy. They will require something of you, but then that is an essential ingredient in a strong relationship. Are you up to it? If so, read on.
Stop -- Stop needing to be right all the time. Sometimes our need to be right overrides our ability to let something go. There are many things in life that are important to be right about: what time the school bus comes in the morning; the location of the concert you plan to attend; the cell number of the babysitter; the name of the cross streets of the hospital where your parent has been rushed! But there are far more things in life that don't much matter whether or not you are the one with the right answer. If you know the war between the those guys and the other ones started in 1931 and your friend insists it started in 1929, let it go. You don't have to be right. Even if it is something of greater consequence, it still may not be important for you to have the last word. Give your friend a chance to be right once in a while!
If there's tension in a relationship, perhaps it is because pride has insisted that it matters who is right. It's time to stop worrying about it.
Look -- Look at the other person and really see him or her. Look at the situation from his/her point of view. Think about the person's background, life experiences, and unique qualities. Get to really know your friend (or spouse!); chances are you will find that person to be much more interesting than you thought. It will be easier for you to identify the source of the conflict if you are really seeing and accepting the other person and giving him or her the freedom to be open and real with you. This creates a healthier environment for the relationship to flourish, and both parties will be enriched because of it.
Listen -- Pay attention. Don't interrupt. Let your friend complete a thought before you devise your retort! If you focus on the other person and listen with your ears, mind, and eyes; if you listen with your body relaxed; if you listen without being threatened; if you listen with the desire of one friend truly wanting to know the other -- I am pretty sure you will develop strong relationships.
The apostle Paul gets the final word here: Be friends who love deeply; practice playing second fiddle. (Romans 12:10, The Message)