It's sometimes just sloppy wording, but note that you'll mainly see that sort of phrasing from women, not men. I think it may portray the thinking of a woman who has accepted polygyny is ok, even good for their family, but is still struggling to fully realise how this works, struggling to realise that it's her husband's business and struggling to trust him with it. Someone who is saying that is on the journey, but not quite at the destination they should reach prior to their husband taking a second wife, they've got more learning to go.
It all takes time, and men need to recognise this, to recognise that their wife might be accepting but actually has more growing to do, so that even though she's saying "go ahead", they should actually wait a bit longer rather than jumping in. Even though it seems the way is clear to proceed, it may still be too early.