I agree with Gilles to say the place of the adjective in French is a delicate issue with few general rules.

With “ancien” you have first to see what noun it qualifies. I have to think very hard to imagine cases when, if ever, I’d use “mon professeur ancien”. First never to mean “my elderly teacher”.
We would not use “ancien” to say a person is old.

Un meuble ancien: an old piece of furniture (or an antique).
Une histoire ancienne: an old story.
Une méthode ancienne: an old-fashioned method.

According to context and stretching ideas very far I suppose in “mon professeur ancien” – if ever used – “ancien” could qualify:

• method of teaching (derogatory)
• appearance (derogatory from speaker’s point of view, “ancien” here not referring to age)
• the number of years he/she’s been teaching in that particular institution we’re talking about.

I suppose other uses could be imagined.

In “ma jolie femme”, “jolie” refers to aesthetic canon.
But if I say “ma femme jolie”, I don’t refer to a certain idea I have of beauty, but I want to say my wife is a sweet or likeable person.

Only some adjectives have two senses regarding if they are placed before or after the noun. Like ancien as you stated it, or also grand: un grand homme (a great man) VS un homme grand (a tall man).

Most of them only have one sense though, and are usually placed before of after the noun depending on the adjective (sometimes both is acceptable).

Regarding your particular example now, ma jolie femme is the correct form and you’ll quite never read ma femme jolie from a native French, as you’ll never find une intelligente femme, which is incorrect, but une femme intelligente.