Complex sentence: It is possible he was the Charles Stewart of Avenue Plains, who had children by a previous marriage (including fourth daughter Isabella who married William Anderson on 17 September 1869) and married a second time, to Mary Wright on 18 June 1864.
Split into simpler sentences: It is possible he was the Charles Stewart of Avenue Plains, who had children by a previous marriage, including fourth daughter Isabella who married William Anderson on 17 September 1869. He married a second time, to Mary Wright on 18 June 1864.