I usually try to aim for sexy-times when we're relatively clean, but honestly neither me or my partner have bothered much. If we're going to have PIV sex, as long as we can take our pants off without knocking the other out with odour we're good to go. However, if there's some oral involved one or both of us will just nip off to the bathroom for a quick rinse - not a full shower, just some water on a washcloth to get rid of any grime. Water is all genitals really need.
Once every other day is fine for general hygeine, and unless you think you're smelling particularly whiffy I wouldn't increase that for sexytimes.
I'd stay far, far away from feminine wipes - trust me when I say that water and a washcloth is all you need. If you're really worried, nip off, wipe down, away you go! (and I'd hazard a guess that yes, soap isn't healthy for your vulva - As soon as I stopped using soap for my labia, I noticed a marked decrease in smell! Sometimes I'll soap up my pubic hair, but otherwise I'm far healthier and cleaner with just water, because my vulva isn't irritated into secreting more.)

Other than that, I'd simply stay well-hydrated and remember that Vagina smells best when it's Vagina. Chemical smelling Vagina isn't very fun for anyone.