Alinity did nothing wrong
Have you talked to her about what she did?
I don't want to stay with a girl who has a stalker
While it's understandable to be put off by a partner who has someone stalking them, it shouldn't be used as an excuse to leave them. You should be supportive and get legal help for your partner in order for them to get rid of their stalker. Ignoring the issue and abandoning them could cause them to be harmed by the stalker.
She should deal with her issues herself. I'm not helping her.
If you're so unwilling to help your partner, she's not going to like your attitude. Your attitude will affect your relationship so if you really want to save it you should help your partner. It's not difficult to go to authorities and complain about stalking.