All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
If the husband has committed himself to pay for the tuition fees of his first wife and she had stipulated that upon conducting their marriage contract, then he must fulfill this obligation. The evidence on this is that Allah the Almighty Says {What means}: "O ye who believe! fulfil (all) obligations." {Al-Ma`idah, 1}. In addition, Narrated `Uqba: The Prophet (PBUH) said: "The stipulations most entitled to be abided by are those with which you are given the right to enjoy the (women's) private parts (i.e. the stipulations of the marriage contract)." {Related by Bukhari}. Also, ‘Amr b. ‘Auf al-Muzani reported the Prophet as saying, “Reconciliation is allowable between Muslims except such as makes unlawful something which is lawful, or makes lawful something which is unlawful ; and Muslims must keep to the conditions they have made…" {Related by Bukhari}.
However, the husband isn`t obliged to pay the value of these tuition fees to his second wife since she hadn`t stipulated this in their marriage contract and he is required to observe justice between his wives after the marriage, not before it. Nevertheless, it is better that he gives his second wife some money to comfort her and Allah Will Reward him for that. We advise all to fear Allah and consort with each other in kindness. And Allah the Almighty Knows Best.