Low Sex Drive in my SO

I'm always the one to initiate sex with my boyfriend. We live together and have sex quite often (almost daily). I asked my boyfriend why I'm the one to always initiate sex and he says once things get going with foreplay it's no problem for him to get in the mood. To me his response just sounds...kinda lazy. I don't know...I just wish he'd make the first move once in awhile. He gets hard just fine, has no performance issues at all, he's not self conscious. He does have a slight medical issue where he has to take pills daily for him to not be dehydrated, maybe it has something to do with his sex drive?