I disagree with this.The extreme opposite of dependence is counterdependence and that isn't a healthy stance as such. In reality everyone has dependency needs and the healthy middle is interdependence. We don't get to the healthy state by suppressing dependency needs. For people who have been counterdependent all their life, that is suppressing all dependency needs and making sure to never need anyone, there needs to be a shift to having these dependency needs met, that is to actually be more dependent, before there is another gradual shift to more healthy interdependence, a shift that will occur naturally after a while.

That is why I think that if you want to force it, for example by pushing through pain or anxiety and then not email, that this is not therapeutic because when the time comes you will simply not feel the need as much anymore and the behavior will decrease on its own.