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 will answer your question in the following points:
Firstly: It is permissible to resort to temporary birth control when necessary but it is not permissible to resort to permanent birth control.
Secondly: It is permissible to resort to birth control by using permissible means such as (a husband) using ‘Azl (coitus interrupts) with the consent of the wife, or (a wife) using contraceptive pills and the like which do not cause any harm.
However, it is not permissible for the wife to refuse to share the bed with her husband (i.e. have sexual intercourse with him) just out of fear of becoming pregnant.
Furthermore, she should know that her husband becoming angry with her due to her refusing his call to bed without a sound reason leads the angels to curse her and makes Allaah angry with her as well, as indicated by the Sharee’ah texts; for more benefit, please refer to Fataawa 88547 and 85402.
Thirdly: the wife should be kind to her husband and should have good marital relations with him. The fact that his family (her in-laws) mistreated her and harmed her does not make the husband bear their sin and he has nothing to do with this as they are the only ones who are responsible for their sins. Therefore, holding the husband responsible for his relatives' mistreatment of his wife is an injustice, especially that he had apologized to her and expressed his love for her and that they have children who are a strong bond. Therefore, we advise her to be keen on achieving what makes this relationship last between her and her husband, and they should tolerate each other's mistakes and errors as much as possible. Each one of them should be good to the other and they should advise and consult each other in regard to pregnancy or other matters that they wish to undertake.
Fourthly: You are not sinful for your wife’s second pregnancy with no sufficient interval between the two children as you mentioned, because you did not exceed the limits of Allaah in this.
Allaah Knows best.