Case of the neurotic ex
Mentally unstable she may be, but hell hath no fury like a woman scorned...and she's got it in for both of you. She'll stop at nothing and sometimes it can get to the point where you feel like she's stalking you. She'll follow you around, slag you off to your friends, and even your kids if you have them (it's been known!). She'll play the sympathy card to get people on her side. Her obsession knows no bounds and she'll drive herself - and you - round the bend trying to win back your other half's affections.
You're torn between hate and pity: she's ruining your life, but at the same time you can feel guilty. You'd love to have her out of your lives for good, but she just won't understand it's over between her and your boyfriend. You try to tell her she's behaving unreasonably but she just won't listen.
How to improve a case of the neurotic ex
You need to show her you're not going to let this go. Be firm and ask your boyfriend to be firm with her as well - it's kinder in the end. Don't be intimidated by her: go about your business as normal, ignoring her completely. The more you have to do with her and the more you notice her, the more she'll be intent on revenge. It will take time but eventually she'll let go when she sees nothing she can do will make the slightest bit of difference to your relationship. Just stay firm with her, and whatever you do, don't start feeling guilty!