My wife gave me the kids then filed a case against me

My wife and I decided t o move to India after a year she moved back to USA for health reason she signed and notarized letter saying I should have the kids . Then she files a case against me for child support which I don't mind paying but I have the kids for most of the time and one of my son is still with me in India for the last 15 years. I want to visit my other kids in the USA but I'm afraid that I might be arrested at the airport and my green card canceled my green doesn't have expiration date