Becwar - Habsburg connection

Around 1840 at Schronbrun Palace - Vienna - Anton Becwar ? was a soldier at the palace who watched over Archduchess Marie Anna Habsburg ?  They fell in love and married.  The Habsburg's disowned her as Anton was a commoner. Anton and Marie Becwar moved to his home town of Prague and had children,  Thehy immigrated about 1848 to USA.  Changed surname to Cooper.  Went to Dubuque, Iowa and died within 6 months of each other,  They died between 1849 -1855.  Any data would be appreciated