“She left me for another woman” or “She left me for a woman”?
Assuming a male speaker is referring to an ex-partner, which of the following is more correct?
- She left me for another woman
- She left me for a woman
The phrase She left me for another man has always made sense to me because the omission of another would suggest that she did not have a man before she left (a subtle self-deprecation on the part of the speaker). Similarly, a female speaker would say He left me for another woman.
Should the rules change when the new partner is of the same gender?
Contrary to the other answers, I think "she left me for another woman" is perfectly fine, and does not imply anything about her earlier relationships (other than with the speaker). It is true that in a sentence like "she left me for another man", the another means other than myself, a meaning which does not apply (since the speaker is male) to "she left me for another woman". But here, "another" can mean other than herself. For instance, in a sentence like "Shane was pleased to see another Australian in Cairo", the "another" only means "other than himself", and does not imply that he'd seen other Australians before. Similarly, "she left me for another woman" does not necessarily imply that she'd been with a woman before, I think.
That said, I think "she left me for a woman" is fine, too. It does not have the problem you mentioned that "she left me for a man" would have (self-deprecation on part of the male speaker), and if some people are going to (mis?)interpret "another woman" as meaning that there was already another "another woman", then it's probably best to avoid "another".
Assuming a male speaker,
She left me for another woman
implies she left the man for a woman, having already been with women in the past. The “another” refers to the fact that there already are women in the woman’s past, and the one she left the man for is one more.
She left me for a woman
implies she left the man for a woman, and this is the first time she has been with a woman, as far as the speaker knows.