art nudes

Frankie
My boyfriend really wants to take part in an art project which involves him modelling nude, he asked me if I'd be okay with it and straight away I said no but he's still considering it. The art project will be displayed at the sixth form college I used to attend and where he is still a student, I'm just not comfortable with his body being seen by hundreds of people, some of which I know. I understand that it's all about empowerment but i just can't stand by it. 
How can I explain why I'm uncomfortable with it?