The OU has a blog on their website that discusses the different waiting times. Search the OUKOSHER site for “the-halachot-of-waiting-between-meals”.
[Original Dutch Jews wait only one hour.]If a woman of German descent, who is accustomed to waiting three hours, marries a man who waits six hours, she must then wait six hours. Similarly, if a woman who waits six hours marries a man of German descent who waits three hours, she may then wait only three hours.