This guy isn't even close to giving up on re-connecting with her in some fashion. He sounds very self-centered, which explains something. The girls he's met, since his breakup with her, didn't stick with him. His self-absorption has probably been turning women off, so he looks back fondly to when there was a girl who hung around for 8 years. Initially, they were kids and she didn't expect real mature behavior from him because they were just kids. Over time, she probably outgrew him, so she moved on. He stayed stuck, to some extent, at age 16, or whatever level he was at during their time together. Then, over the past two years, as he's tried to connect with young women, he hasn't been getting too far. So now he's desperate and wants to try and recover closeness with the one girl who did stick with him for a good while.

Don't be surprised, if he starts calling her with suicide threats. And he may even self-harm. He sees she is pliable. When you talk with her, you might help her see that she is vulnerable to emotional blackmail from this guy. ("Meet me at the coffee shop, or I'm gonna drive my car off a cliff.") Once you start giving in to a blackmailer, it never ends. She needs to nip this in the bud. Otherwise, he'll just escalate in his neediness. She found out, today, that however much attention she gives him, he needs more. He's not going to stop. Only she can stop this, and there is only one way. She has to get uninvolved with him, which means ending communication. (He's so clever, he'll probably then try having a 3rd party call her on his behalf.)

Her pitfall is that she thinks she's got it all under her control. She thinks she can predict how she will respond to him and promise you that she will only do such-and-such and not do this or that. No one can perfectly forecast what they're going to do in a future situation, so her pledges to keep things under control by "shutting down" any inappropriate behavior are not much protection. He knows where all her buttons are, and he's going to push every last one of them.

He's going to manufacture drama anyway he can. If he can't peel her away from you, he'll eventually try to draw you into the drama. He'll be wanting to meet with the both of you, thinking you will more readily agree to that. Don't get sucked in. He's already got the two of you upset with each other, which is exactly what he wants. He's getting off on thinking about how the two of you are talking about him. He's made himself a presence in your home already. That's why I don't advise you to have long, deep conversations about him with her. That's what he wants. Keep it short and sweet. Otherwise, before you know it, he'll be showing up at your summertime barbecues. This guy needs to get a life (of his own.) He hasn't really got one that's going too well, which is why he's trying to move into yours.

Your girlfriend has to get a clear, consistent message from you that there is no room in the life she and you have together for this guy - none. That means that he is not even a fit subject of conversation between the two of you from here on in.

You're right about this guy being manipulative, and I'll bet he's got a bottomless bag full of ploys to use. The only way to deal with someone like that is to not deal with him at all.