H, As with all DB tactics, watch to see wether they work or not. Distancing is no different.
There are two reasons to distance yourself from H. First, So you can escape the pain associated with watching his crisis. 2nd, to better enable you to focus on your own issues and growth.
In many cases, the detatched spouses senses the withdrawl and begins to draw closer or pursue. It is a pretty natural occurance. If your distancing yeilds negative results, you can always back off and try something different.
If your gonna distance, don't tell H about it. Just do it. Then watch the reaction. Make sure you give it some time. At least a couple of weeks unless real negative results occur.