Agree - and:
(a) if you have so little faith in the guy that you suspect he'd run off with your "better-looking" friend at the first chance he gets, then why are you with him?
(b) likewise, if you have so little faith in your so-called friend that you suspect she'd run off with your romantic interest at the first chance she gets, then why are you friends with her?
Exactly. I know it's easier said and done, but the OP is not doing herself any favors by worrying so much about guys choosing her friends over her. The insecurity does shine through and when it comes to her guy friends asking her girlfriends out, it might not have anything to do with them being better looking or more successul and everything to do with confidence levels.
Trust me when I say that working to keep a guy interested is not worth it. As hard as it is to let go, it is better. If he's going to choose to date the model, he's going to do it no matter how hard the OP tries to keep them apart (and I understand she gave the contact). If the model is interested in him, the OP not giving business contact isn't going to stop her from meeting him.
This reminds me of a time many moons ago when I had an enormous crush on a guy friend of mine. He flirted with me, we hung out alone (wouldn't call them dates), and I truly believed he was interested in me. He told me how great I was and how he really admired my character and could fall in love with me if he let himself. Then, he met my "hot" friend and just like that I was pushed to the side and he was all about her. (In her defense, I have always been pretty secretive about my crushes, so she didn't know how I felt). It hurt me more than anything to see them together and I did think that if I was thinner, wore my clothes differently, was more flirtatious, or whatever, that he would have wanted me. And that was probably true...but that wouldn't have been me. I regreted introducing them. I got mad at her. But the truth was, this guy wasn't worth the trouble. When they broke up a few months later, he came back to me. He said he learned his lesson and wanted to be with a "good" person like me. But it was too little, too late. I basically told him that it was a great lesson to learn and he should apply it the next good person he meets. If I started da
ting him I'd always worry that he'd dump me for the next prettier girl...and that didn't sound like a good time to me.
When I met my now DH, it was totally different. My best friend introduced us at a party. At that same party was my other, size 0, model looking friend. I was used to the guys always liking her and when DH approached us both at the same time, I assumed it was her he wanted to talk to. But that wasn't the case. He has always been interested in me...the whole part of me. Looks, personality, everything. And I've never once felt threatened by another woman, no matter how awesome she is. Because I'm confident in his love for me. We've been married for a long time...have had our ups and downs, but that confidence has always been steadfast.
I know it's hard. I know it hurts. But if this photographer guy would really drop you for your model friend, then he's not worth da
ting. And if your model friend would purposely pursue him, right under your nose, then she's not your friend. If they get together, then take it as a lessoned learned that neither of them are your friends.
That being said, are you and the photographer really pursuing something? If you really think that he'll hook up with this girl, is there a slight possibility that you are way more invested in the time you spent together than he is. Is it possible that he isn't yet committed to you in the same way you are to him?