What do you do with the crazy ex girlfriend?

ok this is a long question so those who don't like to read... move on. I have been dating a guy for about 5 months now. we were friends for about 2 years before that. been there for each other though some rough breakups and eventually decided to start dating. things between us are great we have fun are honest and open and love each other we have fought maybe once but were quick to forgive and its forgotten now.the thing is his ex girlfriend.she keeps texting him.now i don't want to be the girlfriend who says you cant do this you cant be her friend ladedah.its his life he can have his friends I trust him. but she just keeps stepping in she lives in a different state so she wont visit and she wont call but she will text. I have talked to my boyfriend he knows I don't like her He knows I don't trust her but he also knows I left it up to him. I have tried ignoring her she wont go away he has tried ignoring her text messages and she will keep texing and texting until she gets a response. he cannot turn off his cell because his dad has medical issues and if he needs help my boyfriends the one they contact.I have tried talking to his ex asking her whats up she said she was moving on and just wanted to ask him something then move on, that was a lie and all she ended up doing was haring him about getting back together. he tells me things and doesn't hide things from me so i know. so i don't trust her and i am angry with her.I have tried tlaking I have tried ignoring i have tried getting in her face. she willnot back off.or she will stop tlaking to him for a month then start up again. its always a month spand then she comes back.I love my boiyfriend but he is a bit of a pushover I am working on this iwht him but he has a hard time saying no pive but not a wimp just too sweet for his own good. so he is saying i can do whatever i feel is right regarding her and he will do it because he chooses me over her.it would relese a lot of tension if she were gone but then i would feel like i was telling him what to go and taking over. i dont want to be controlling but i want her gone so what should I do? ok sorry for the typo's im not the best speller for some reason spell check here just stopped in the middle and i cant get it to come back.