You shouldn't need the windows open constantly. A couple of 'purges' a day will help. A window open during cooking and showering will also help, if you're drying anything too, even if just a bit. The building regs is 5000sq mm background trickle ventilation to a habitable room. If that trickle...
There's only some symptoms you'll be able to reduce in terms of producing vapour. Drying clothes on radiators as an example releases a huge amount of vapour/moisture, and if you have to do that, it has to be done with a window open ideally. Check your extract fans are working in kitchen and...