Keeping a marriage together is a task that should not be out of obligation, but should be done because of the love and respect each partner has for each other. While courtship, marriage then divorce seem to be a regular stage in a person's life, this could be totally eradicated. Being married for 3 decades or more should not be seen as triumph but a necessity.
The decision of getting married should be given multiple thinking over. Although you love a person and has deep devotion and loyalty, a lot of changes happen while inside a marriage that can change the way a person feels for one another.
The key is to keep the marriage exciting at all times. Every relationship has space for improvement. Improving your marriage is something each and every married person should strive for. If you keep your marriage from becoming predictable and monotonous you give a reason for you and your partner something to look forward to and get excited about.
Each partner should be open to changes. Learn to experiment and accept those changes. Being adventurous both in your daily activities and in the bed room will keep the relationship young. Learn to accept your partner even through his or her changes. The person you married is not the same one that he or she is now or next year and the years after. People change, and if those changes do not affect your vows try to be accepting and flexible.
Role playing can be a great idea to keep the relationship fresh. This could not be counted as cheating so do not be jealous. Although you may play games wherein you imagine the person is a different one, you still both know deep inside that it is your partner. Having an open mind can improve your marriage a whole lot.