Pre-marital therapy: do it.
I think most folks would agree that premarital therapy is a good idea just on the principle of the thing. Still wondering? Get this: 40% of married persons describe themselves as happy with their lives, and even worse, only 18% of divorced persons do (source). "Marriage therapy is the best insurance you'll ever buy" is a great quote from one of the articles I link to below.
Although anything is better than nothing, seeing the pastor a few times (etc.) is not as effective as ALSO seeing a relationship expert, such as an LMFT or someone with specific training in pre-marital therapy. Regardless, the key to effective pre-marital therapy is in anticipating the worst conflict areas, exploring them, and learning effective methods of arguing about them in the future.
The critical take-home point is that arguing is good. Debate, even heated debate, is good. Arguing is how big decisions get made in a marriage. We get the idea that arguing is bad because most of our parents had/have bad marriages (if yours didn't, congratulations). Poor arguing is all about control, and that hurts. So we learn to avoid. But avoidance, as the researcher and therapy John Gottman so famously proved, is the single largest predictor of divorce. Good argument, however, is co-constructive, and you can learn this skill in pre-marital therapy.
I'll give you a couple articles here, but I want to highlight a great quote from one of them:
"Why so many couples avoid pre-marital counseling - or counseling early in the marriage, for that matter - has to do with fear. At root, most men and women fear that talking openly about problems with a counselor will lead to even more problems and the eventual dissolution of the relationship. But please hear me when I say that the reality is counter-intuitive! Though it can be scary to vent your anger, frustration and resentments, it is the release of these feelings in a structured context that actually allows two people to move past them and later start liking each other again."
Link to article from Psychology Today