It's because she sees the children as her property and extensions of herself. It's all about control, IG doesn't want to be with or see her anymore so he can't see her property (the kids). Him working away would have added to her entitlement over them (not blaming him he had to go to work to provide).
I can’t work out what her plan is with custody. She wants 100% I assume to hurt Ioan and for more money. Let’s face it she didn’t love Ioan - she loved the money and celebrity life (appearances as she admitted). There is no way she can get full custody infact if Ioan went for full he would likely get it due to her having a PRO. She has no job, clear evidence of PA and spousal abuse and a PRO. She is in dream land. Even if the kids refuse to go to Ioan she still won’t get full custody. If she wants to continue the PA and encourage them not to go to their dad then that is on her and she will have to deal with them 100% of time but have a 50/50 agreement. She is again shooting herself in the foot.