Not sure I follow you guys on this. Why is it a concern at all if the woman knows you're married? So what? As long as you don't give out your name, it's useless information.
Let's pretend the nightmare scenario happens and you're seen in public, with your wife, by the MPA. How many of these girls do you think are going to walk up and say, "Hey, I jerk your husband off for $40.00 from time to time". That's like a drug dealer shouting across the mall, "Hey, you need any more drugs that I can sell you?". Discretion is important to them too.
Except for one lady, I've never had an MPA act reluctant because of my wedding ring. Usually it's the reverse. When they know you're married they also tend to think of you as a guy who's there just for the fun, no strings, and not looking for anything else. The married guy is the perfect customer. So lighten up.