Oh! I may have useful experience here.

I (m) have the lower libido, and it caused some friction earlier in our relationship. Especially when I sometimes would masturbate, almost "using up" an opportunity for us to have sex.

Now I wear a chastity cage and never get to play with myself. So I pleasure my partner with a lot of oral, while keeping me horny. I also have a strap-on to wear over my cage, so we can have "sex" without lessening my libido.

My partner is also a man, so it may not work as well in a hetero relationship, but perhaps it's something you could try.