It doesn't have to mean he thinks you're physically unattractive, he may just be not really interested in sex too much at the moment for whatever reason.
Once a week is not something I'd consider to be "not often," either. It's not going at it like rabbits, sure, but it's not like it's a rare event. You may simply have a higher libido than he does and as much as that sucks, I'm not sure much can be done unless one is suffering from an extremely low libido for some sort of health reason.
I do understand what it's like to feel so on the outer when other women are talking about their partner nagging them for sex, and yours never does. This was me with my ex. He didn't have sex with me for 6 monthly incriments normally, and it was horrible. Made me feel like absolute rubbish.
I'd let your partner know how you're feeling, but also add that you don't expect him to just suck it up and have sex with you if he doesn't feel like it... but perhaps if ther'es a reason why he doesn't want sex, it's something you can work on together.