[Pyromaniac]

The tricky thing is that, for women, all that talking tends to create a male-female attachment. Don't you think? A man takes an interest in her ideas/thoughts/dreams/interests...makes her laugh...pays attention to her...that can be the start of a great friendship. (It can also be the setup for great sex, too. I guess that's where the wall comes in.)

Walls and flirting. Some women/relationships, a man/woman can't flirt. Flirting leads to f***ing.

Other relationships, a man/woman *can* flirt because they *know* there won't be any f***ing.

Back to the OP's GF...probably she realizes that sometimes these female-friend-relationships lead nowhere and sometimes they lead to cheating--so just easier to say, Don't have any of them. And not worry about sorting it out.