 He (like the Duke of Wellington whose marriage failed for very similar reasons) was simply unprepared for the reality that his wife's personality and youth was not going to live up to his high expectations.That she was mere 16 to his 27 at the time of marriage and that he is said to have blamed her for the death of their only child cannot be overlooked as a probable source of misery for Eliza.As divorce was not an option at the time they may have ended up feeling trapped in a loveless (and in this case childless) marriage.