Crazy ex girlfriend

Hello everyone.. I am currently dating a man who has a crazy ex girlfriend and by crazy I mean a legit psychopath.. I don't know what to do to get her to leave him (and myself) alone. She calls him 24/7 and texts him even though he doesn't answer. She will literally call 3 hours straight off the hook. She stalks him (ie chases him when she sees him, she found out where we were staying and she's doing laps outside of the hotel and inside the hotel. She will come at like 1 in the morning and knock for an hour straight) also because I could be possibly pregnant she said if I didn't have an abortion she should give me a home abortion. She is threatening to take the kids away from him and when he wants to see the kids he can't because he will go over there to see the KIDS and spend time with the KIDS and she will cause a big scene and start screaming and yelling and it really upsets the kids so it's not fair for him to go over there and make them all so upset... Please help, I restraining order won't help and I honestly think the only way to stop her is to move out of the country (literally) but I'm not even sure that will even stop her. PLEASE SOMEONE HELP... This is so draining having to go through this everyday.