WIll the US recognize a german divorce if........?

[Mystic]

the marriage happened in the united states. My boyfriend was married to a german. THey were married in OKlahoma. She is german and never obtained us citizenship. They moved to germany and lived for sometime but he never got german citizenship. When they seperated he left germany to work in iraq and made his home of record back in oklahoma and moved back here six months before the divorce. She filed for divorce in germany and it happened last week. Given he is a us citizen and they were married here in oklahoma is the german divorce legal here?
year old guy, I am having a hard time relating your examples to my boyfriends divorce......

Each state in the us list reasons that are acceptable to divorce another...the state of oklahoma list this as a reason........

a spouse divorcing in another country without oklahoma being contacted or knowledgeable of the proceedings....that leads me to believe that Oklahoma won't recognize the divorce in germany, but I am not clear on it by any means