IMHO, this is bad news.  This may get convoluted, so bear with me.  Also, I understand that I am not perfect, so take this FWIW.

Taking your relationship to the next level requires a certain level of trust.  By its nature, the hobby is a breach of trust if the hobbyist has a significant other who is unaware of what is going on.  In your case, you both know of your active participation in the hobby in the past, which may be tough to get past.

Also, the next level suggests that you are looking to have an exclusive relationship with each other.  It sounds like you may not be ready for that, so again, bad news.

Unless you are willing to give up the hobby, you may need to find
someone who is unaware of your hobbying or someone who is willing to share you.  

Again, JMHO.
BKMan

Relationship (business or other)? Next Level, exclusive (your business only or other)? What's fair for one, is fair for the other (if both agreed). Why walk away from what you wanted to do in the first place? Yes, you both should aways listen to your inner voices and follow your instincts (better judgement). Probably better not to confuse being a hobbyist with looking for an SO.

Well, if you feel that you just absolutely have to try this new talent you speak of, then it would seem you're not ready to be exclusive.  Remember that she is going to be giving up her livlihood, while you are only giving up a hobby.  I hope you two can work it out.  The odds are against it, but if you both want it to work out, it will.  Let us know how it goes.

I've got this image of myself opening up the fridge, drinking milk out of the carton, with only the cats getting pissed.  I'm old, I'm bitter, but hey, I do whatever I want.  Freedom!

you say, "against the better judgement of both parties."  That's worth talking about.

you say she'll be exclusive, and that she'll quit her job.  Will she move in with you too?  Are you thinking marriage?

maybe slow down a little, maybe she keeps working, maybe you both continue to see other people.  Options are good, plans are better.  

Be brave - definately have "the conversation"!  If you don't, the relationship is doomed!  

good luck, fahrkle

I don't think I'm in a positon to advise.  For all I know I have a conflict of interest.  On the chance that your potential SO who might be forced to leave the business is a favorite of mine, I am tempted to advise that this can never work.

OTH, I am a hopeless romantic.

Go for it.  Leave the hobby behind. Try to make it work.  

But do not tell her you are going to give it up without intending to do so, and really doing so.

If, after some period of time, you then find you are unable to continue to be outside the hobby, you have the same problem faced by all the hobbyists out there who are attached, but "super-sized".  Your specific promise will make it more difficult to adopt, even for yourself, all the rationalizaations and excuses others wo are attached adopt to justify these activities.

Nevertheless, my vote is to go for it.

By relationship I assume you mean committed realtionship, if so,
you are the reason why divorce rates are through the roof. You talk of commitment like it is jacket to be taken on and off as you feel the need.
Stay the course, you are a true hobbyist.

you live for now and not tomorrow to be blunt.

You can try to plan for tomorrow but unless the girl is really sick of the business and wants to totally change her lifestyle and go in a different direction, this is heading for a really big crash and burn. I had a somewhat similar experience and it got really ugly at the end.

Do yourself a big favor, move on.
Go for the new talent and don't look back
Yeah, I know, easier said than done, but just keep progressing forward

There are a few pieces of information that might help clarify what your relationship is now and what it will be.  First will you be supporting her once she quits the business or will she pay her own way.  Will you move in together, are you considering marriage.

If you will be the one paying everything, has she really left the business or is she just working for one guy.  If that is the case neither one of you has really left the hobby.  In that case I would say hobby on.  If you are planning on eventually going to marry then I would say stop the hobby.  However I do not think it is fair to make you quit before she quits.  It is very hard for a man to know that his significant other is having sex with numerous guys and you are suppose to be monogamous.  I have been there and it took a much better man then myself to live that life.

I would say that you both quit at the same time and then be true to each other.  Remember that the hardest person to cheat on is a ex provider.  She will know if you stray.  She will know what to look for and where to look for it.

If you continue down the road to a committed relationship I wish you both well.  As I and others have mentioned many times, you may be able to walk away, but will you be able to stay away.  Will you look for new talent and constantly wonder what it might have been like. Will you be able to put it all behind you and be happy with one person. Be true to your own feelings and then decide what will be best for the both of you. If you are not going to be happy I can guarantee you that she will not be happy either.

I would offer you a few questions rather than advice.
1. Can you both survive a relationship that started " Against the better judgement of both parties?
2.  When " for both of you " does the Exclusive part  start? Does it start when you/she say it or practice it. What is the definition of Exclusive and do you both agree on it ?
3.  What is fair? Is it fair you give up the hobby OR is it fair she give up a way she makes income?
4. You say you " would have walked away from the hobby, but some new talent has emerged in San Diego that I abosutely have to try" How exclusive is that?
5.  She " agreed to exit the business Sometime early summer " How exclusive is that?
6. What is it that you both REALLY want?
I hope it helps......

It's been a good discussion, and Harleydude did an excellent job of summarizing the issues. I could see why anyone would have second thoughts.  But if you're going to back out, do it straight out like a man.

The line about the new talent that you "absolutely have to try" sets off alarm bells.  Sounds an awful lot like the rest of this is just an excuse to free you to enjoy the new talent while making it all her fault.  If I'm wrong, I'm wrong, but try reading what you wrote as if you were a stranger reading those words.

It makes no sense:

You aren't ready to commit to jack shit from the way you express your thoughts.  Be honest with yourself and don't F up somebody else's life.  JMHO.