Dating

Am I overthinking the reasoning behind my boyfriends low sex drive?

When my now boyfriend and I first met he was fairly known to be very promiscuous. After about a year of friendship, we started dating. His past never bothered me and before we started dating he would often brag about his experience and high sex drive. After we started dating, I quickly realised how much of a wonderful boyfriend he is and things would be perfect except for one thing. He has almost completely lost his sex drive, never initiating and gets annoyed when I try. I find him incredibly attractive and want to jump his bones any chance I get, but it makes me feel undesirable when he breaks contact or tries to redirect the subject all together. I've tried talking to him about this, but he just said that he isn't sure why his drive is gone and also feels like an ass because I mentioned it. Am I ridiculous for thinking there is a link between starting dating me and his low sex drive? He says he's incredibly happy, so should I just overlook this one factor in an overwise amazing relationship?
Am I overthinking the reasoning behind my boyfriends low sex drive?
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