Over at Psychology Today there's a special collection on 'The Power of Fathers'. This includes an interesting piece on how involved fathers diminish mothers' self-confidence.
Even though they still spent almost three times as much time care giving
as their husbands, the mothers' self-competence ratings
dropped--essentially "the more time their husbands spent engaged in
skillful care giving, the lower the self-competence of mothers sank."
That's certainly not my experience: as ever, I would be interested to hear the views of others.