Responses
Agreed but also you forget this is a normal trope where a man can have a legal wife and a mistress and no one bats an eye.
So FL was probably going to be kept as a mistress and any kids she had would become the legal wife's children...
Then the sister could use that as leverage to torture the FL even more.

Tf you mean you're just going to marry both sisters?!
Disgusting mf..