husband not in the mood

My husband and I have been married for 8 years (together for 16) and have a great marriage. We're best friends and enjoy spending time together, however, we rarely have sex anymore. I hear this is fairly common but it's usually because the woman isn't in the mood or the couple is too tired from dealing with kids all day. I'm actually the one trying to initiate sex but I'm usually turned down. When I try to talk to my husband about our sex life (or lack thereof) he gets defensive. I'm trying to figure out if it could be because of a medical issue (low testosterone that I keep hearing about on tv) or if he's just sick of having sex with me, or if he's no longer attracted to me. We're only in our late 30s and generally healthy + we don't have children. I'm baffled. Any advice?

Put the internet to work for you. via Personal Recipe 2629979