Hmm, let's see, we've been married almost 25 years now. We have sex probably, on average, 5 times a week. We tried an experiment back in 2000 (we were married 17 years by then) where we had sex just about every day. It really does depend on your partner. I was lucky enough to find a real minx.
And yes, we really do have sex about 5 times a week, no bullshit.