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 have already issued Fataawa 99468 and 84856 clarifying that the wife is obliged to live with her husband wherever he resides unless she has a legitimate reason to justify her refusal, or unless she had stipulated in the marriage contract that he should not take her out of her country.
What you have mentioned about him being of dubious character, or him threatening you with divorce, or him being prone to hitting, all this does not justify refusing to obey him in moving abroad with him. If it were assumed that he is unjust to you, then you should advise him in a good and gentle manner. If he stops his injustice, then this is what is required; otherwise, you may take the matter to the concerned authorities who can deter him and give you your right, such as an Islamic court, if any, or what serves in its place, like Islamic Centers in non-Muslim countries.
If you are wise in dealing with your husband, and you exert an effort to be a dutiful wife, perhaps Allaah will enable you to have a stable life with him. You should also make the existence of your son and your acting in his best interest a means for reaching a mutual understanding with your husband.
Custody of this child is a right to both of you as long as the bond of marriage is ongoing. In case divorce takes place, you have the right to custody of your son as long as you do not remarry. In case you remarry, the custody is transferred to the women who are more deserving of his custody according to the sequence mentioned by the scholars. Please refer to Fatwa 84618. We hope that the matter does not escalate to divorce, and we hope that you reconcile.
Finally, it should be noted that the husband is Islamically required to have good marital relationship with his wife and vice-versa. Allaah says (what means): {And due to the wives is similar to what is expected of them, according to what is reasonable. But the men have a degree over them [in responsibility and authority]. And Allaah is Exalted in Might and Wise.}[Quran 2:228]
Therefore, each spouse has to fulfill the rights of the other with respect to him, and it is in this manner that a marriage becomes stable. For more benefit on these rights, please refer to Fataawa 85308, 88304 and 83157.
In case the wife or the husband becomes negligent (concerning the rights of their marriage partner), then the Sharee'ah has specified how to deal with each of them as discussed in Fataawa 85402 and 97217.
Allaah Knows best.