Complex sentence: Deciding that he wanted to become a U.S. citizen, he married 22-year-old Amy Jersild Duhnke in 1981 in Madison, Wisconsin, purportedly to obtain his green card.
Split into simpler sentences: Deciding that he wanted to become a U.S. citizen, he sought a woman who would marry him. He married 22-year-old Amy Jersild Duhnke in 1981 in Madison, Wisconsin, purportedly to obtain his green card.