A - Thanks for the question! Unfortunately the information you were given was wrong. While it doesn't directly answer your question the Catechism has a short paragraph on infertile couples:
2379 The Gospel shows that physical sterility is not an absolute evil. Spouses who still suffer from infertility after exhausting legitimate medical procedures should unite themselves with the Lord's Cross, the source of all spiritual fecundity. They can give expression to their generosity by adopting abandoned children or performing demanding services for others.Only those who are intentionally infertile by means of surgery, drugs or device are doing anything wrong. But, even then, the vocation is not determined by this. Even in your example nothing was wrong, because the intent was not to make the woman infertile, but rather to treat an illness.
Not every marriage must will bear children. This does not mean that it isn't a valid or good marriage. Many sterile couples are more free to devote themselves to the works of mercy or other apostolates. Children are a gift from God, but not every couples is blessed with this gift. This is not the fault of the couple that is infertile and therefore has no bearing on their vocation.
I hope this helps.