A band is not a marriage. There are no oaths of allegiance. If you feel your life will be better served by splitting up the group you've got to do it - but of course it does cause problems.
When I was deputy chairman I could travel from Glasgow to Edinburgh without leaving Tory land. In a two-week period I covered every constituency in which we had an MP. There were 14. Now we have only one. We appear to have given up.