First of all, in answer to the OP, she'll be turned on by other guys just like other women will turn you on. But she's interested in you ultimately.

As far as the flirting goes, you have to gauge that. Harmless flirting means nothing because she'll shoot them down. Guys flirt with Mrs. Webgoji and I let her handle it until it gets out of hand. Once Dexter La Jock starts to get a little out of hand though, I step in. For example:

Sexy Eye Doctor - "I think you've got more going on than eye issues."
Mrs. Webgoji - "I'm just a freak!" *giggling*
Sexy Eye Doctor - "I'd have to do other tests to figure that out!" *laughing*
Webgoij - "Like hell you will while I'm around."

Situation diffused.

Now if it gets out of hand and you step in, but you're GF gets mad about it, then dump her like last weeks garbage.