I really like that about you, that you own up to doing things that might be problematic. (For that matter, I've written fic without women, dammit, and I was so pissed when I noticed.) The girl who exists to be supportive is definitely difficult, because you run the risk of on the one hand positing that two guys in love can't handle it without a helpful girl who knows about emotions, and, like you said, it takes away her right to be her own person. It's even worse when she's the girlfriend of one of them, sigh sigh sigh.