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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
We ask Allaah The Exalted to relieve your distress and bless you with a lawful source of income. We advise you to be patient and to supplicate Allaah and to remember Him and thank Him frequently; Allaah, The Exalted, says (what means): {Those who have believed and whose hearts are assured by the remembrance of Allaah. Unquestionably, by the remembrance of Allaah hearts are assured."} [Quran 13:28]
You should know that a Muslim's property is lawful in principle and one should believe that his fellow Muslim has earned his money through lawful means except if proven otherwise. It is a duty on the Muslim to have good thoughts about his fellow Muslims and it is prohibited for one to think ill of them; Allaah, The Exalted, says (what means): {O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin.} [Quran 49:12]
Therefore, you should not investigate the source of the gold any further, especially since your in-laws have clarified to you how your wife acquired it. For more benefit, please refer to Fataawa 87422 and 123876.
It is noble of a wife to help her husband with the household expenses and other expenses. In addition to being charity and kindness to her family, it is a means of earning her husband's love and kindness towards her. Please refer to Fataawa 92004 and 103083.
To sum up, the money your wife offers you is not unlawful if she offers it to help you, not as a dower as is customary in India. We have underlined in Fatwa 85873 that the dower system in India is un-Islamic. Hence, there is no blame on you for accepting that money from her. You are advised to repel such bad thoughts that depress you. This is the work of the devil so seek refuge in Allaah from his evil.
Allaah Knows best.