I'm a US citizen and my wife is from Australia. About 3 years ago we applied for a K1 visa for her to come to the US and we had 3 months to get married, and we did that. However, after we got married she stayed with me there (US) for about 8 months and we decided to live in Australia. Now 2 years later, we both want to go back (US) and visit my family. My question is can she go back with a simple ESTA? Would they stop her from re-entering? We didn't fill any forms or anything after we got married within the 3 months. I'd just like her to go back with me and visit family. What problems might we incur?
I would telephone the local US consulate in Australia an make an appointment to discuss the situation. Immigration rules are very specific in the US and it is likely since the follow up paperwork was not supplied that your wife does not enjoy the status she would have. Please speak with the officials before you start your journey. My guess is she will have to come in with a tourist visa for a short visit. My wide is also not from the US an we relocated there twice, ad after leaving the first time gave back the green card ad needed to apply again when we moved there the 2nd time.