It seems to me, that outside of infidelity, physical abuse or addiction, most marital problems are caused by differences of opinion about 1)money issues, 2)time spent with each other and/or 3)how household and family responsibilities are to be shared. The most important thing to me, it would seem is to make sure that both spouses come to agreement about those core issues. How that is accomplished is a very much a function of the individual personalities involved.
I must be one of those rare people who know many couples who have been happily married for ten to fifteen years. Not a single one them would tell you that they haven't encountered serious difficulties with their spouses at one time or another.