In the comments for my open post a few days ago, Julie mentioned wanting my opinion on writing romance from a male perspective. She also requested a post on writing "Dad" characters, which I might talk about later.
But anyway, one of the things you first have to understand when writing a romance from a male perspective is that most guys are not nearly as observant as romance novels make them out to be. I speak from experience when I say that, nine times out of ten, it's better for the women in our lives to tell us -- in a direct and clear manner -- what they want for their birthdays/Christmas rather than leave it up to our discretion. (Ask my wife about the first necklace I gave her if you want an entertaining story about my lack of observation skills.)
In SON OF MAGIC, the main female character (Astrid) is in love with the main male character (Swain) and has been for years. They're best friends and spend practically every moment they can together. Does Swain realize that Astrid's got a crush on him? Of course not.
Now, barring the fact this makes for more entertaining reading, this is a common occurrence with men and women who are friends first and romantically involved second. At least one of them (typically the guy) is clueless as to the other side's attraction. He knows he likes spending time with said girl, but beyond that he's entirely oblivious to how madly in love with him she is.
How to write this?
Well it depends on your male character's attitude. Is he the calm, courteous type or the angry, jealous breed? Does he talk a lot or is he mostly terse and uncommunicative? Is he brilliant and driven by a desire to succeed or does he lounge about and let events act on him instead of the other way around? All of these character traits determine how he reacts to the woman in the story.
One of the things to remember as well is that most guys won't put up with a woman who doesn't know her own mind for long. If she's hot one minute and then cold the next, he's more likely to give up (unless the point of your story is to unravel that aspect of her personality).
This is why romance novels are so skewed -- the men in those novels are conceived of from a woman's perspective with how she feels a man should act in a given situation. A man reading those novels (of which I've read precisely one) looks at this and goes "Wait a minute. No guy would ever say/do that."
TWILIGHT is a particular offender in this category. No guy in their right mind (even a vampire) would climb into his crush's room and watch her sleep. He'd know that's creepier than anything except maybe Hannibal Lecter in a tutu.
Anyway, I hope that answered your question Julie. Feel free to ask any followups if you want.