They are not the same.
Sarah who married Thompson has parents Capt. John Welles and Elizabeth Bourne, and the Sarah who married Benjamin Beach has parents John Wells, Sr and Sarah Curtis.
based on -
https://www.wikitree.com/wiki/Welles-51
https://www.wikitree.com/wiki/Wells-9829
https://ancestors.familysearch.org/en/MQ89-8QD/sarah-welles-1658-1730
https://www.familysearch.org/tree/person/details/9312-TN6
I’ve added more sourcing to these couples, so it should be more self evident in profiles now.
Sarah Thompson married Ambrose Thompson
Sarah Beach married Benjamin Beach