Shootingstar, I like the way you stated this. Maybe more nicely than I did! My DH and I are pretty much like you and your partner, although our level of involvement is pretty much even... although DH commutes to work and I am in school and can't commute right now. I will go back to that when I get a job (one of my main requirements for employment is that it's easily accessible by bike).
Sometimes I think we are the only couple who is happy being together almost all of the time. Interestingly, both of my kids are the same way with their SOs. Despite having some different interests (including cycling), they still make the relationship a priority.
I remember, about 15 years ago, my mom told me a few months before she died, that DH and I should find a common interest to do together, as our kids were getting to the age where they were starting to go off on their own a lot more. Little did she know...