I assume you mean, so he could marry Wallis Simpson?

It's important to note that these two monarchs existed on differing sides of a very important document -- the 1689 Bill of Rights. Among other things, this Bill severely curtailed the powers of the monarch, as well as setting out certain rights that Parliament had.

Specifically, the role of Supreme Governor of the Church of England is largely ceremonial. There's no longer any "just" reforming the church, the way there was in Henry VIII's day, when there was an absolute monarchy.