To some extent, most of males like to look at women’s body, either nude or partly revealing. It is natural urge and on which whole entertainment industry, advertising industry, internet etc are surviving. As far as, he is not hooked on it or replacing his sexual life to this habit, it’s fine. For your doubting nature you need to work out because it may have its roots to your early life experiences, your and your husband’s personality, your other relations, your surroundings etc. Try to introspect and analyze. Take help of an expert, if needed.