A foreign judgment shall be conclusive as to any matter thereby directly adjudicated upon between the same parties or between parties under whom they or any of them claim litigating under the same title except-
(a) where it has not been pronounced by a Court of competent jurisdiction;
(b) where it has not been given on the merits of the case;
(c) where it appears on the face of the proceedings to be founded on an incorrect view of international law or a refusal to recognise the law of India in cases in which such law is applicable;
(d) where the proceedings in which the judgment was obtained are opposed to natural justice;
(e) where it has been obtained by fraud;
(f) where it sustains a claim founded on a breach of any law in force in India.
So these six conditions are fulfilled by such foreign judgment/decree of divorce then it will be valid for dissolving such Indian marriage as has been held by the Supreme Court of India in several of its judgments.
If your wife has accepted the authority of US court, it cannot be open to her to later question the authority of the US court.
Decree of Divorce by a foreign Court is also valid in India if there is no challenge by the other party. If both of you go for mutual consent divorce, then it is recognised and valid in India.