An-Nisa 4:20

Wa-in aradtumu istibdala zawjin makanazawjin waataytum ihdahunna qintaranfala ta/khuthoo minhu shay-an ata/khuthoonahubuhtanan wa-ithman mubeena

But if you want to replace one wife with another and you have given one of them a great amount [in gifts], do not take [back] from it anything. Would you take it in injustice and manifest sin?

If you want to take a wife in place of the one (you have), and you have given her plenty of wealth, then do not take any of it back. Would you take it through imputation and open sin?