I had this question last year, got my husband to make up a timeline, and he could not come up with the correct date (607). He was off by a few years. He didn't think that was a big deal, but then I asked how we know 1914 is correct if the years are off? He soon realized that we can't really be sure of any dates, including 537, 607 and 1914.
The book Gentile Times Reconsidered has lots of facts to show 607 isn't the date. My husband didn't read that book though because he didn't like the "tone," and felt it was apostate.
After a year, my husband is beginning to realize things aren't making sense with this religion. I planted a few seeds, and then totally backed off. Like your wife, I also believed that the GB was God's mouthpiece. What got me was the new generation teaching. Everything I learned as a child has now been changed (generation, sealing of 144K in 1935, number of memorial partakers going up). Why did Jehovah inspire the GB to write things and later change them? If this keeps happening, why should we believe anything they say now if it's going to be obsolete in 15-20 years? I mentioned those questions to my husband and hoped they would grow.
*Check your PM*