Rather than becoming harder, life actually got much easier, because they no longer had the added burden of taking care of the people who were supposed to be their partners or dealing with the many negative emotions their spouses elicited from them.
What they had feared prior to taking action never manifested.
There are other factors in marriages that, if present, indicate a low probability that the relationship will ever be healthy or fulfilling. If both parties are willing to put in the work that the marriage requires, the chances of the problems and issues being resolved increase dramatically.
However, even when both spouses want the marriage to last, there are some situations that lack enough of the necessary ingredients to keep it afloat.
** This is true unless one or both of you have a no-tolerance policy.