not sexy..?

At the start of my relationship my S/O and I had a decently high sex drive. I was 17 and he was 18 and at the time we're both virgins so I guess that'll explain the higher sex drive. We're now 20 and 21. I've noticed lately that we haven't been having sex as often as before which was around two or three times a week (maybe). Now it's around one time a week if I'm lucky. I've tried being adventurous with our sex and I've tried dressing more sexy but it just feels like he's not interested in me anymore. I've tried to understand that we both work and go to school, but there should be time for some US time in there. 
Recently I stopped wearing makeup because I'm a nanny and I want to promote a more positive body and self love to the girls especially. I am not 100% happy with how I look without makeup but they don't know that. So I honestly do kinda want him to be all over me now because in a way I'll still feel the way I do with makeup on and even a little more sexy. Also he is ALWAYS more horney when I'm on my period (which I normally will help him with), he won't go down on me unless it's a"special occasion", and I've noticed he will actually watch TV when we do have sex. Am I not trying hard enough or ...?