First the couple can each sit down and look at their own faults and try to rid themselves of it. Both the couple can sit down together and see what are the problems and how they can solve it together while keeping the love they have for each other. It is important not to play the blame game.
Another way is to seek advise and counseling from someone who knows both the couple and their behaviour, is wise and their well wisher and is able to speak to the couple separately and bring them together through the love the couple have for each other. Although it is necessary that the couple should also want to solve the problem. This person should NOT be one who favours one side and has no control over his/her anger