Getting married very young, getting married due to a kid, getting married after dating for a short period, working in shitty jobs, living in certain states, marrying someone who has ever been unfaithful, marrying someone who has ever experienced a divorce before.
Not trying suggest one should not necessarily avoid anyone who falls into the above. But, while I cannot find any raw datasets to try and estimate this for myself, most of this have independent effects of double digit drops. Assuming a practical amount of multicollinearity, I would wager my best predicted probability of divorce is lower than 10% without considering any personal beliefs on our relationship.
Heck just looking at single variable analyses from various studies I see reason to believe my predicted divorce rate is 30-60% lower than baseline.
First marriages have an average divorce rate that is 20% lower than the average rate. Marriages in my state have an average divorce rate that is half the US average.
You can do much better than the top level average.
But if you save up an entire year's salary after a few years, that should be more than enough for some lawyers...
Edit: not clear if a once-wed person marrying a newbie counts as a first or second though. I’d imagine that could be significant.
But more seriously… if you aren’t willing to take a guaranteed decently large pay increase (which scales with future income growth) with the added chance of losing more to legal fees and arbitration later on… you probably shouldn’t get married. You’re probably correct that for a middle class family the pure fiscal return will likely be positive if your marriage lasts just a handful of years.