I do believe that a couple should take a long and close look at their values, goals, and feelings between the time they decide to get married and when they actually do. One way to do this is using pre-marital counseling with an effective counselor.
But I think that such counselors are very rare, whether we are talking about therapists, ministers, or (like myself) relationship coaches.
So, I would encourage the couple to read ways of being a healthy couple together, including the 5 Love Languages, by Gary Chapman (see my hub on this); The Way of Council by Jack Zimmerman, and works by spiritual couples who are roll models for them. My wife adds Getting to Yes, by Fisher and Ury (the technique that brought peace between Israel and Egypt may just be necessary in your marriage!) And, if children are planned, read a book like Models of Love by Barry & Joyce Vissell, and agree on what kind of parents you want to be.
Do all that, and maybe some premarital counseling, too.
"Before anything else, preparation is the key to success."
Alexander Graham Bell