Sadly, roughly half of marriages in the US end up in divorce. However, the reasons for divorce are well-documented and steps can be taken to address the potential for it.
Finances, Finances, Finances!
Financial reasons are the top of the list for divorce. Make sure your financial goals are compatible. Too many couples find out later in life that they have different goals. One partner may believe in saving up for an early retirement while the other lives paycheck to paycheck and spends more than they take in. What’s more: both may believe in the virtues of saving up and not spending incessantly but one may not practice what they preach and spend impulsively. This is something that needs to be communicated and worked out.
Communication, Communication, Communication!
Financial matters above are one of the reasons communication is important. But finances aside, make sure you are both on the same page regarding other goals in life (children vs career vs traveling, living standards and location, religious expectations) and both have compatible expectations on etiquette (social life, friends of the opposite sex).
Family of Origin
Get to know your partner’s family. This will often explain their behaviors and habits. Do they come from a quiet and etiquette-conscious family? Perhaps they come from a loud boisterous family where being quiet and reserved is frowned upon and seen as cause for suspicion? It will be especially important to understand your spouse’s family if you come from different cultures/ethnicities where nuances and expectations are entirely different.