As a provider, discretion isn't something that should asked of.....it should be something that's a given. Also, as a provider, you should give your clients a referral because you don't own the client. Variety is the spice of life, if the client just wanted one piece of ass, he'd stick with his wife or SO.
If you're unwilling to give references, you're in the wrong business and will not succeed. It takes a village to keep the village safe.