I spend loads of time on AB, but it's because I work for myself and spend a lot of time on the computer anyway, so I skive off and play on Ab a lot. My partner is very busy as well and doesn't mind what I do, as I'm on the computer anyway so it doesn't make any difference to her.
As much time as I like. My husband asks me to put questions on and asks who has been on and I try to get his opinion on some things before I answer too.