Joke about doctor and slut

"Doctor, I need your help," the woman says.
- "What seems to be the problem?"
- "My husband just doesn't satisfy me sexually. What can I do?"
- "Hmmm. That's a bit out of my league. Has HE seen a doctor?"
- "Yes, he has. He is perfectly OK. He just isn't enough for me. You've got to help me!"