Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Islamic Shariah encourages Muslims to give birth to many babies in order to increase the number of Muslims. The Prophet (Sallallahu Alaihi wa Sallam) said: "Marry women who are more loving and very prolific, for I shall out number the people by you".
Therefore, this husband should not refrain from having more children without any legal reason. However, for a reason one may abstain from having children for a temporary period.
We advise both the husband and the wife to solve the matter with mutual understanding in the light of Shariah and not to follow their desires.
In fact, a husband is not allowed to ejaculate his sperm out of his wife or even to use condoms without the consent of his wife since she has the full right to enjoy sex and have children. This is clearly mentioned by Muslim scholars.
Allah knows best.