Why isn't Prince Charles in the same situation as King Edward who married Wallis Simpson?

Answer 1

There has never been any rule that the person who would otherwise be the heir to the throne was disqualified by being divorced.

The whole Edward VIII/Wallis Simpson problem was rather different. Back in the 1930s divorce was seen as inherently shameful and "divorcee" was, for the majority of people, a synonym for "woman no better than she should be". Even then there was no actual law that the King couldn't marry a divorcee (though, since this marriage could not take place in church, it would certainly have caused problems re the King's role as Head of the Church of England). But it was felt that the nation as a whole would revolt at the prospect of having an immoral woman as Queen Consort, and Britain would go republican in disgust.

These days of course divorce is socially acceptable and even the church has gone a long way towards accepting it.

Answer 2

Edward was warned not to marry her because of her divorce and reputation and he was all ready king when he did. Charles isn't king and may not be for a long time. As it is his wife has now been given a title, but she will never be queen. There also is a possibility that Charles could give the kingship to William.