There are several husband and several wives
As long as their is truce and the condition for such marriage is acceptable by both parties, and the subsequent others.
This choice is for the humans to make , we have that liberty, the modern society especially that of india is very punishing to those who believe in personal liberty, meanwhile these liberty are give to us by very gods and the chetna and budhhi that we have
As far as karma is considered,
A- NO, a bad karma would be if someone would be hurt by that said marraige, if there is agreed conscious couple marrying after taking the agreement of the other person, it is justified. The other parties do play a role in it.
Subhadra also had to be accepted by Draupadi .
So yes, it's acceptable, but norms in this yuga, especially of current society are not as moderate for those principles and the ruling govt often regulate private choices .