This fact has been revealed by a former Islamic State militant
This is raising concerns about the fates of the three British girls who entered Syria for the same exact purpose. Amira Abase, Shamima Begum and Kadiza Sultana, aged 15 and 16, passed the Syrian border to join the extremists.
Apparently, women who succeed to arrive there are forced to marry older IS commanders for one week and become their sex-slaves. After this, they are divorced, and forced to marry another man for the same reason. And, unfortunately, this process is repeating itself on and on.
Concerns are raising because women represent 10-20% of the Europeans who join the IS. This is dubious due to the constant reports of women being forced into slavery, enforced domestication and rape.