How am I supposed to feel about this?

I have been in a serious relationship for about three years and neither of us have ever strayed from the relationship. I really need to know if Im overreacting to this issue we are currently having though and cant really ask my friends because their biased. My boyfriend loves to take pictures of scantily clad women if you catch my drift and so far he has had two women pose for him. He has three more lined up and they are all going to be charged or at least thats what he tells me. Im not allowed to be around when he does this because he feels I will make them uncomfortable (which could be true). It just really bothers me because he wont take pictures of me and I dont understand why. Im not a super thin person but definately not unattractively large. The girls he takes pictures of are around a size 2-6 but... ahhhh Im just so frustrated. He knows this infuriates and hurts me but he says its the one crazy thing I should let him do and be supportive but its very hard. HELP!