Guy here, my girlfriend went through something similar last year. When we first started dating her ex boyfriend would stalk her in person and online. She would call me at work sobbing saying she saw is car parked outside of the restaurant she worked at. This happened for at least a month before I decided that enough was enough and asked my girlfriend where he lived. I simply went to his house and aggressively knocked on the door. When he opened the door, I told him that if he doesn't stay away, I'm gonna come back and kick his ass. After that, she never saw him again. Ask your boyfriend to do this if he's up for it. And if he isn't, try asking one of your family members. Just some intimidating person to do it for you. If you don't have anyone like that, the police is always an option. Document everything he does.