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.
It is not an obligation on a wife to keep ties with her in-laws if they are not her relatives, but she is not permitted to desert them except for a sound reason like dissoluteness and the like.
Having good relations with the in-laws is something Islamically required as a way to maintain the relationship that Allaah has made between the wife and the family of her husband.
Besides, it is not permissible for you to prevent your child in the future from keeping ties with the family of his father without a sound reason as this is helping in cutting ties of kinship. For more benefit, kindly refer to Fatwa 83096.
As regards the promise (which your in-laws made to your husband), the jurists differed in opinion about the ruling on keeping the promise and we have already discussed their opinions in Fatwa 86010, so please refer to it. In that Fatwa, we opted for the opinion of the Maaliki School and a group of scholars that a promise that would incur harm on the person to whom one has made the promise, it is an obligation to fulfill it unless one has a valid reason for not doing so. Therefore, if your husband has undertaken this marriage based on the promise of his family, then they are obliged to fulfill the promise that they had made to him.
Nonetheless, it is better for your husband to seek the help of Allaah and look for a living that would suffice him from asking people.
With regard to your statement, ‘I married against my parents’, if what you meant is that they were not pleased with your marriage but this marriage was concluded with the consent of your guardian and the presence of two witnesses, then this is a valid marriage, given that if the parents object to the marriage without a sound reason, then it is not an obligation to obey them in this regard. For more benefit, please refer to Fatwa 157379.
In case this marriage took place without the consent of your guardian, then it is a void marriage and it must be invalidated, and then you have to renew the contract while fulfilling the conditions and pillars of a correct marriage contract in case you and your husband wish to continue your marital life. For more benefit on the conditions of a valid marriage, please refer to Fatwa 83629.
Allaah Knows best.