It is usually easier to file for bankruptcy before getting married. In Chapter 7 bankruptcy, it can be beneficial to do so earlier so that you are not bringing debts into the relationship.
It is also likely easier to qualify through the means test to file a Chapter 7 case when you only need to use your income. Once you are married you will need to show household income, so if your spouse is a higher earner, you may not qualify for a Chapter 7 anymore.
If you and your spouse-to-be already have significant joint debts, however, you might be better off waiting and filing a joint case together. To learn more, check out our article on this in our Learning Center.