I guess the first step would for you to find the civil marriage license which should help you find the church where the ceremony was performed.

I suspect the church records should still exist unless the church was destroyed by fire or some other calamity.

Once you find a location in Lithuania, you can begin to see how far back their records may exist. Unfortunately, many of the churches in Suvalkija were destroyed along with many church records from fighting in WW I and WW II.

Tom