I'm so glad you were able to get the PO. I would still be cautious though. You just never know what he might do. Maybe it was all just talk, but a PO is just a piece of paper and will only stop someone who is willing to obey the law.
If at all possible, I'd still get the security system and maybe some pepper spray to carry in your purse. I'm really not trying to frighten you, but I'm sure you know that sometimes, things happen even when there is a PO in place.