Men are visual - period. Looking at bikini-clad females isn't a sin or a crime, but his denial is something that might possibly cause problems down the road. It may be a wise choice to sit down and rationally discuss your feelings, listen to his feelings, and come to some understanding as to how you both might better communicate your needs to one another. A healthy companionship and partnership precludes the need for deciet - there are some things that my spouse will never know about my past, but we make an effort to keep our communications honest and open. I can take anything that anyone has to say or divulge, but I cannot (WILL not) tolerate deception.
I'm a female and an artist, and I thorougly appreciate the use of nude female forms in artistic expression. The human form is something that has long-since been turned into a marketing tool and has been ruined as a form of aesthetic beauty by our current culture.