Is controlling purging meant to be this easy?

I think the best thing for you is to just recognize that it's a problem. It'll help you to stop. Maybe set rules for yourself about how much you'll allow yourself to eat all this junk food, and reward yourself somehow when you follow them. I don't think your boyfriend is being supportive enough. It's a psychological thing that you're going through, and I guess he just doesn't understand that. He's partially right in that you need to exercise some self-control here, but it'll take a lot of work. If you don't stop this soon, you'll get to a point at which you don't even need to "force yourself" to vomit - it'll happen automatically. DO NOT let yourself go that far! Good luck. *Gives asker a hug*