I think it goes away if only because you'll get sick of making yourself sick and make no mistake, you are making yourself sick. Amy, if you're going to be serious about cutting him off (as you stated) you have to do a better job of prepping yourself to do that. What I mean is, maybe you did have to call him today but if that's true, did you run through it in your head first? Did you tell yourself that you were going to talk about exactly what needed to be said and nothing more? Did you remind yourself to be calm, clear and detached? Did you take deep breaths, remind yourself of your goals and move from there? If you fail to prepare, prepare to fail.
You know this stuff, you know what you have to do. I'm not lecturing you, God knows I'd be the pot calling the kettle black, I'm just trying to remind you that you cannot go halfway with this thing. This sometimes strong, sometimes needy thing you're doing is only going to make it that much harder for you down the road. He's (rightly) seeing this behavior as a lack of commitment on your part to change and when he starts to see sincere change in the future, he won't believe it because he's seen this back and forth too many times. Eventually, when he does believe it, things may be too late for you. Do yourself a favor, take yourself off the roller coaster.