This is tough, when I read this I first thought, man up and tell her! Sure her feelings might get hurt but at least you don't have to go months with her stalking you, and plus she probably knows what's up. If before that the two of them were shagging every damn day and after he got her picture the shagging stopped and he didn't want to spend as much time with her, then I feel she would probably know. Plus people shouldn't get so butt hurt over what people think you look like and if they find you Hawt or sexy. Beauty is in the eye of the beholder, if that person things you aren't attractive, move one, but don't go crazy and create a hate group.
However, Im in a similar situation, or at least I could be. My partner and I have become extremely close and enjoy what the other has to bring into the relationship, we aren't exclusive in RL because RL is RL sl is sl, yaddah yaddah, if I got the 10k to ship myself over to the UK I don't know that I would so quickly just to be with him ANYWAY! I was talking with a friend and she and I talked about this. I know Im attractive and many guys and girls find me attractive, so no skin off my back if one person didn't think so. But if I saw him and he was Pounds and goofy looking I don't think I can have the same relationship. Humans are very visual, the reason we are sexually attracted to one type or the next is because our animal instinct is telling us "This person is a good mating buddy, have many babies with them" why do we not find 400lb men with goofy faces attractive? Because the animal instinct in us tells us that that's bad genetics. So Even I, a female have some visual needs. And Like wise if he didn't find me attractive, it wouldn't kill me, because I know Im pretty I feel pretty, more power to the haters etc.
So Like I said its tough on one hand you want the guy to just tell the girl and you want the girl to not get so but ass hurt, but I know many women who are my friends and I've said "Man your sl boobs make you look a little thick" (not obese or fat or lard ass) 'thick' and they've totally gone nuts over that little itty bitty thing. So tough question, tough answers I guess case by case right?