Many abusive people make this threat as a way of getting their partner to stay in the relationship. It isn’t true.
If social services do become involved with your family their main aim is to ensure that the children are safe and being looked after to a reasonable standard. If they have concerns about your relationship with your children they will talk these through with you and try to ensure that you have the help and support you need. It is only in extreme cases that children are taken into care.