Jenna, I'm an alcoholic. I haven't had a drink in 20 yrs, but I do sometimes have strong urges to drink--because I'm still an alcoholic. The thing about addiction (I believe) is that it's a lifetime thing. Not everyone agrees; they think they can be cured, and go on to use moderately. I think if I have even one drink, chances are I'll be back drinking drunk in no time.
As an alcoholic, I'm also easily addicted to pain killers, which are in the same general category of drugs. I have to find other ways to cope with pain, such as acupuncture.
Rather than go through the agony of trying to "control" your addiction to Ritalin (or make your fiancé responsible) could you talk to your mdoc? I don't know that there are alternative treatments, but it's worth checking.
I hope you can face the reality of being an addict, or it's going to be very hard for you. Letting your doctor know what you're going through would be a good step. It's not going away, and coping with it now will make your life lots easier. Get other viewpoints, but get solid medical advice.
Take good care of you.