All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the wife had conditioned on her husband before marriage that he should not marry again and he accepted this condition, then the wife who put the condition has the right that her condition be fulfilled according to the most preponderant opinion of the jurists . For more benefit on the stipulations in the marriage contract, please refer to Fatwa 92334. If the husband does not fulfill this condition, then the wife has the right to ask for divorce as stated by the scholars who are of the view that the husband is obligated to fulfill this condition.
As regards marrying again in your circumstance while believing that this will be a solution to your financial problems, then you are wrong. Abu Hurayrah narrated that the Prophet said: “There are three kinds of people who have the right on Allaah to help them: the Mujaahid (fighter) in the Way of Allaah, the Mukaatab (the slave who has a written deed of emancipation in return for a sum to be paid in installments to his master) who wants freedom, and the one who is going to marry therewith he seeks chastity.” [At-Tirmithi and An-Nasaa’i]; this means seeking to be chaste from Zina (adultery) and you are not seeking to get married for this purpose. In addition to this, it is only the person who is able to meet the marriage expenses who may marry, as in the authentic Hadeeth: “O, young people! Whoever can marry should marry, as it helps to lower one’s gaze, and protects one’s private parts (from committing illegal sexual intercourse).” [Al-Bukhari and Muslim] The ability here refers to both the ability to have sexual intercourse and the ability to meet the expenses of marriage as Ibn Hajar considered this to be the preponderant opinion.
Therefore, we do not advise you to marry again since you are in this condition of financial problems, in addition to other disadvantages that you fear from your second wife in case you marry another wife.
Indeed, there are many other means to increase sustenance, among which are supplicating to Allaah, obedience to Allaah, keeping ties with kinship, and seeking forgiveness as much as possible and so forth.
Allaah Knows best.