They both want your money. but the SO will remind you that it is time to mow the grass, take out the trash, and Dont forget her maxi-pads at Walmart. And the SO will always have a headache when your head is aching for attention.
You still pay for sex with the SO you just dont know when you are going to get it, as for the provider you know what you are going to get when you pay.
A true SO parts her lips (either pair or both!) because she wants you in there.
A Provider is providing a service that is based on receiving compensation based upon the level or type of service.
A true SO doesn't require you to schedule an appointment, a Provider wll.
A true SO doesn't require references and, after some length of time, agrees to mutual booty calls.
A true SO swallows. A Provider might allow CIM.
A true SO can be trusted with your home phone number and address. A Provider with similar information carries the risk of having it fall into the wrong hands.