I'm curious why you would say this. Would that be a bad thing to the ISTJ if she did let him control her? And if that is a bad thing, then why would the ISTJ even try to do it in the first place?
I don't think they TRY to do it. I think it just kind of... happens. They do it without even knowing it. I don't even know if "control" is a good word for this. Personally, I've never "controlled" anyone before, but I do know xSTJ's that have and it's mostly the annoying or "unhealthy" ones [not to worry Oregon, I'm sure he just doesn't realize what he's doing], I think.
In my opinion the ESTJ's are especially good at controlling people, but a few ISTJ's can do it too I guess.
But letting them continue to do it just lets them think "oh, well, everything is ok s/he doesn't seem to mind." When in reality, the other person is really annoyed/hurting emotionally.
If I EVER was in a situation where I was "controlling" someone, I would want to know immediately, so I could stop. The LAST thing I would want to do is control somone, I can barely control myself!
Bottom line: YOU MUST COMMUNICATE
IN BLUNT TERMS WITH YOUR ISTJ WHAT YOUR EMOTIONS ARE! If you do this, it will solve and prevent lots of problems!

ESPECIALLY if your an ENFP!
