These answers have been great so far. Mucho, mucho lurve.
@tb1570: I left the details vague to hear how everyone would act under different conditions, which leaves me with things to consider when I’m writing fictional stuff. So if I would have given you more details, I’d have lost out on those conditions. Though to oversimplify it, I could try and put you in the guy’s shoes and say this much:
You’re single, but not sure if she is. There are rumors that she’s involved with someone else, but she won’t confirm this. Your relationship is initially professional with her. As a journalist, your job has brought you to her and you’re trying to get a story out of her, so you need to work with her in order to get it. (I don’t mean to make it sound so straight-forward and impersonal, but that’s sorta how it is for him, lol.)
Anyways, the more you work with her the more you realize that there’s a growing spark between you two. After a couple of weeks you decide to try and advance things a little, and she doesn’t respond favorably. That’s when she tells you she’s been engaged. Actually, she just got engaged a couple of days ago, haha.
Thing is, the more time you spend with her, the more she wants to grow closer to you and the less she wants to talk about her fiancé. Still, you’ve committed yourself to this story, pretty lady or not, and you’re determined to get it. (The story he’s after actually goes beyond her and has some deeper sentimental value to him; it’s just he realizes that she’s connected to it and needs her help to get some answers.)
What makes this fictional situation different than it would in our society is that her fiancé lives in a country where polygamy is legal. By law, its citizens, male and female, are allowed to have up to three spouses. Though this woman lives in the same country as you (or him), half of her ethnicity comes from her mother being a citizen of the country where polygamy is acceptable. She can’t practice polygamy, but her fiancé can.
So that’s sort of the dumbed down version of where this question came from. :P I do like my characters to be kinda complex.