The trouble with abuse is that it causes you to question yourself. You are told continually that whatever "punishment" you receive, it is your fault. If you hadn't done something then they, the abuser, wouldn't have had to act that way. You get into a pattern of continually questioning your own actions and after a time, you become convinced that you could have controlled the situation better. Consequently, when you part and things go wrong, you do miss the abuser who has normally controlled everything. I can absolutely see why she thought she wanted him back. You may have to be out of the situation for many years before you become independent of that sort of person and some women never manage it.