I was married in argentina,I moved to the states 11 years ago,my ex wife told me she got divorce done.
3 years later I got married here and have two kids,I lost all contact with my ex wife,if she never filed for divorce is my marriage legal here and I'm permanet resident now,can this change?
Thank you

If your not divorced, you are still married to her. In the US, you cannot be married to 2 people at the same time, so your second "marriage" is not yet effective.

Did your "second" wife file for you? If so, you needed to provide your divorce papers in the petition.