Is it normal to want to see my brother in law naked

I visit my sister and her husband regulary, like as least 3 times a month for the weekend. I tried everything possible just to see him naked! Its not that I am gay or anything, just curious. I even talked to him and said because I don't have any brothers and only sisters, that I want to feel how it feel to walk in a room when he is bathing, because living with only sisters and a mother I never experienced it to have a brother. I thought that would feel like having a brother. But now it became an obsession. And still I haven't seen him naked. Is this normal?