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. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Marital life has many noble objectives; any other worldly pleasures are meaningless compared to it. One of these objectives is the stability of life. This is an objective that the husband and wife have to work together to achieve, by helping one another and understanding each other regarding marital life matters. The issues that your question comprised will be summarized as follows:
First Point: Islamicly, you are not obliged to spend anything on things that your husband is obliged to provide. It is solely his responsibility.
Second Point: Your volunteering to help is a strong incentive to foster friendship, affection and the continuity of marital life.
Third Point: It is not permissible for your husband to interfere in the money that you possess as long as you spend it in what is permissible.
Fourth Point: You do not have to repay any portion of the loan that your husband took.
Fifth Point: Your husband is not obliged Islamicly to accept your two children from a previous marriage. If they are still at the age of fostering, you are not entitled to foster them since you are married to a second husband. The responsibility for their fostering belongs to the female relatives who are more appropriate to foster them, or to their father if he is suitable for that, and it is the obligation of their father to spend on them. So, we advise you to discuss each of there matters with your husband in the light of the information we have provided. Both of you have to see how unity and stability can be maintained in your marital life. This should be the first priority.
Allaah knows best.