I don't have much of a leg to stand on with relationships, but I thought I'd throw a couple cents in. I would like to agree and possibly elaborate on Bubbleboy's post, if he doesn't mind.
Yes, for me at least, it's not a matter of control --- it's a matter of knowing where I stand, where you stand, etc. I just need to know where everything's at. Unfortunately, in life, I often resort to "controlling" my situations that way I can guarantee these things have a certain "location". So, don't think of control as the ultimate ISTJ goal, it's more like a side-effect to wanting a solid ground to stand on. (a solid past to reference, if you will.)
Now, not to stack the cards against you, but if you're truly as fickle as your posts would make you, here is where I imagine the friction occurs. He doesn't like you being fickle because it makes it impossible for him to form a....knowledge of where you both stand. (Because you change, on the outside at least, too frequently.) While you find a lack of predictability "fun", or "normal", an ISTJ would find that tortuous. (at least I do.)
I would recommend a compromise under normal circumstances, but unless you would both be happy with a compromise, then it would be pointless indeed. A relationship should be mutually-beneficial --- and as an ISTJ *would* say --- like a business contract.
Just take it seriously, and take it slow. You have to strike a balance between letting him have "control" as you call it, and you being "fickle" (for lack of a positive form of the word.) (Spontaneous doesn't quite fit.)
Ah, but of course, take it with a grain of salt. I am no professional --- I merely think I know it all. Have a good day. ; )