Complex sentence: While waiting in Connecticut to meet-up with Smith, Brannan fell in love with Ann Eliza Corwin whose mother took care of the visitors in the local boarding house and planned to marry her and separate from his first wife.
Split into simpler sentences: While waiting in Connecticut to meet-up with Smith, Brannan fell in love with Ann Eliza Corwin whose mother took care of the visitors in the local boarding house. Brannan planned to marry her and separate from his first wife.