I wouldn't say my DH has a low sex drive...I think I just have a very high one.
I have read that progesterone cream in very small doses on men is like a natural viagra. I was using progesterone cream a couple of years ago, and I would put it on my skin before bed, and I noticed during those few months we were dtd almost every single day, and it was my DH initiating all the time. I think the small amount that transferred from my skin to his did the trick! So maybe worth looking into.
I've also heard that Maca (a supplement) can increase libido in men & women, but I have no experience with it.
Good luck.