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I wish I had married a different man.
Literal
Different man [with-と] marry do-[if-ば] was-good [despite-のに] [regret-なあ].
~すればよかったのに expresses regret about not having done something — 'if only I had done X.' The なあ at the end adds a wistful, sighing quality. 結婚する takes と for the marriage partner. A strongly emotional sentence of retrospective regret.