The father has right to child custody if parents live in separate lands
5-7-2014 | IslamWeb
Question:
Salamu alaykum wa rahmatulahi wa barakatu I want to make Hijra to a country that is far better in terms of Islam than the country i am living in.. But I am married to a woman who has 2 children with a person that lives in our country. So my wife was divorced but the children are still his ( her ex-man) children. I really want to make Hijra as Belgium does not offer the Islamic options that the country I am willing to move to does. I really want to study in either Medina or England together with my wife. But her ex-man does not allow this and he is a muslim. I am really confused and I ask Allah help in this because my dream is to be most close to my Creator, and Belgium is not the way I am going to be most close to Him. So what now, will I have to stay all my life in this country if the ex-man decides so? I do not want to leave my wife... I appreciate a fast response, barakAllahu feek
Answer:
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.
First of all, you should know that the ruling on migration differs according to the circumstances of the person. For instance, migration is obligatory upon anyone who fears that his faith is at risk. So, if this is your case, then migration is obligatory upon you.
In any case, whether or not migration is obligatory upon you (in particular), and you would anyway like to migrate from this country, then it is incumbent on your wife to reside wherever you do. Muslim jurists stated this with some conditions. Mawaahib Al-Jaleel, authored by Al-Hattaab Al-Maaliki, reads: "A man may travel with his wife if her safety is ensured. Ibn ‘Arafah said: ' ... on the condition that the [travel] and the place where he is moving to are safe.” [End of quote]
If your wife travels with you, then the father of those children has the right to custody of them; Shaykh Ibn Taymiyyah 
said in Al-Fataawa Al-Kubra, "... if the father is residing in a country other than that of the mother, then the custody [of the children] belongs to him and not to the mother, even though the mother has more right to the children's custody if [the father and the mother] are living in the same country. This is also the view chosen by the Imaams of the Four Schools of jurisprudence.” [End of quote]
For more information, please refer to Fatwa 89647.
Some jurists conditioned that, for the father have right to the custody of the child, he must have a female who is suitable for looking after the child.
Therefore, if the father of those children has the right to their custody, then you should try to persuade him to allow them to travel with their mother; and if you do not find a way for that, and it is possible for you to stay with your wife, then you should do so, and endeavor to keep company with righteous people and attend circles of knowledge in Islamic Centers there, and so forth.
Finally, if there is no other alternative than divorcing your wife, then do so, and Allaah will suffice each of you with some of His Bounty. Allaah says (what means): {But if they separate [by divorce], Allaah will enrich each [of them] from His abundance. And ever is Allaah Encompassing and Wise.}[Quran 4:130]
Allaah Knows best.