On August 15, 2010, New York State adopted a law allowing for divorce without proof that the other partner to the marriage was at fault. All of the other states in the United States had already adopted "no fault" divorce.
The law took as long as it did to be adopted mostly because some supporters of it believed that it gave wives more bargaining power on substantive issues in a divorce. The downside of fault based divorce is that it required couples to engage in the well poisoning business of fighting over past acts that damaged the relationship. A part of the process that does long term harm to the parties without itself providing much benefit ultimately needs to change.
The late revision also illustrates the fact that just because New York State law is often chosen in choice of law clauses, mostly for the convenience of lawyers based there (hey, I'm admitted in New York and really shouldn't complain), that doesn't mean that there is anything particularly good about its substantive law. Indeed, more often than not, New York State is a less desirable, rather than a more desirable forum from a substantive law perspective.