In theory, if two people get along, it should not matter what they do for a living. In theory.
Unfortunately, real life is less theoretical than we'd sometimes like. When two people having fun together starts to transition into an actual relationship, most of us expect certain things from our partners. While everyone has a different take on what's acceptable in a relationship, most men (and women) tend to expect that certain intimate activities are exclusive to the relationship.
It's easy to say, in theory, that what she does as an SP is simply business and has no emotional component. She provides her customers a service for money but when she comes home to you she's really feeling what she's doing and she's doing it for you. In theory.
However, then you remember that you were once her customer too and that it changed into something else. What if she meets someone else the same way? Now you start to worry about who she's meeting on her SP calls and wondering, when she gets back to you, whether her other customers really didn't mean anything to her.
You kiss her and can't help wondering how many mouths were there earlier in the day, you slip your tongue into her mouth and wonder if your technique is as good as one of the guys she saw that afternoon, you make love to her and can't help remembering that you're not going where no man has gone before (you're not even going where no man has gone earlier that day).
These feelings are real and can interfere with the natural growth of the relationship. Remember, you haven't known her that long and you don't have the confidence, early in the relationship, to truly believe that you are special enough that she won't get interested in someone else the way she fell for you a couple of weeks ago.
Perhaps, if you have a long-standing relationship with a woman, have developed a strong bond of trust, and you both have the self confidence to know that you mean a great deal to each other on many levels, you might be able to accept her being an SP. It's quite different trying to build a new relationship with that kind of baggage from day one.
I've written about this before and I still believe it is true. While it may not be impossible, I think it is very difficult for a working SP to build a true romantic and serious relationship with another man who knows what she does. This is not because there is anything wrong with her, it is simply because, as humans, we're not wired to appreciate sharing our most intimate partners.
If the lady is a former SP or drops out of active work as the relationship gets more serious, I think there is much better potential for success. However, if she's committed to keep working, it's unlikely that you can take the relationship beyond a casual level. You may be able to build a friendship and you may be able to have a lot of fun together...but a true and serious romantic relationship is highly unlikely to end well in this situation.