Marriage Contract with Two Husbands

Roseline was married to Grand Duke Melchor, the empire’s number one knight.
“You don’t know anything about me.”
“I want to save you.”
A man who wanted to save her life, save her family, pay off her debts, was now proposing for marriage. There is no hidden favor, but why would he do this to someone he barely knows?
“You look like someone I know.”
Melchor’s first love looks precisely like Roseline.
While Rosaline was depressed because she thought she was just a stand-in for his first love, she took Julian who resembles his husband.
“Please divorce that man and marry me, Roseline.”
What happens when she marries both men?