Is it permissible to abandon a Muslim wife (the mother of one's children) and desire to marry a Christian woman after her conversion to Islam?

"Religion is 'naseeha' (sincere advice). Your friend committed a sin by loving a foreign Christian girl, and this is not a justification for abandoning his first wife and committing injustice. An error is not corrected by another error. Polygyny requires justice between wives in terms of lodging and financial support. Your friend should avoid illicit relationships, strive against his desires, and fear Allah."