Does Christ need more Brides in his Harem?

I've been doing a lot of talking, thanks to a cousin, and also an old girlfriend, about theology as of late- I'm being pulled back in to that fascinating topic for me, the life cycle of sects in religion and why schisms happen. It's a fascinating topic for me because it's also largely a mystery to me.

What I still don't get, as an outsider looking in- Why does Christ need more Brides in his Harem? Ever since the Reformation (and despite being Roman Catholic, I do recognize that Martin Luther fulfilled a valid need- I'm very much a child of Vatican II) we've been splitting apart the Church, the Bride of Christ, into thousands, nay, tens of thousands independent bickering brides over the slightest differences in theology.

The challenge I'd present to the emergent movement from the liturgical side of the Church, the very people who defined Orthodoxy to begin with, is why split away? Why form new churches? What the heck was so wrong with the way of the Apostles anyway, from the Didache and the Early Church Fathers and the Bible, that you have to run out and form something new? What is so wrong with Orthodoxy that you must run away from it, be exclusionary against it, and create anew that which was already created for you to be nourished by and learn from?

We already have a Pope (and he's in Rome, not Montana, as some on the entirely opposite side of the debate would claim), so why do we need more?