Your Brytteva Jonsdatter Mestad was 1st married to Nils Knutson Ekse. They had 5 children: Breta, Knute, Storre Nels, John and Vesle Nels. Nils died in 1861 in Big Canoe, IA. Brytteva then married Nils' brother, Johannes Knudsen Ekse. Johannes was killed in the 1862 Belmont Massacre. Brytteva and the children then went back to using Brytteva's "Mestad" name, from the farm in Norway. It was not another marriage.
Just send me an email and I'll be happy to send a chart to you. firstname.lastname@example.org
The story about your Mestad family is published in Astri, My Astri: Norwegian Heritage Stories by Deb Nelson Gourley and also in History of the Norwegian Settlements by Hjalmar Rued Holand (1908 book translated to English).
For more info visit http://www.astrimyastri.com