A happy marital life means good understanding and respect with your spouse. See every relationship has its ups and downs that is because when two people who are from totally different background want to go the same path, there are bound to be differences of opinions. Some times when these differences are taken as problems then relationship ends. However when these differences are taken with a positive attitude and equal opportunity is given to adjust and correct, then the relationship not only lasts long but also is healthy with self respect for each partner.
I always feel it is not possible to avoid problems, but it is important to learn to tackle them and once we learn this art then everything in life , can be marital relationship, job , friends, day to day challenges become earlier to handle.