Elizabth Bowes-Lyon was allegedly in love with another man, someone who was definitely not considered suitable.
It has been argued that she was not wholly convinced about the wisdom of marrying into the RF, and the life of royal duty and loss of freedom that would ensue.
It might however have been the rather less than prepossessing charms of Bertie that were the major stumbling block. Slight of stature and afflicted with a crippling stammer, he was certainly not such an eligible parti when compared to his elegant and chartismatic brother David. It has also been said that Elizabeth had an eye on the bigger picture and hoped that she might land the bigger fish and thus rejected the proposals of the younger, less attractive brother with the less glittering prospects. If this was the case, imagine her chagrin at losing out to the sophisticated, brittle and elegant divorcee Wallis Windsor...(it might explain some of her bitter enmity towards the Dss of Windsor?)
As Tsaria rightly suggests, she does seem to have formed a genuine attachment to her husband, although rumours abound of domestic violence and alchohol abuse. True enough it is that she took to the life of queen like a duck to water, and never enjoyed anything les than truly regal style, even in her long years of widowhood.