Thank you mambo, attitude and laura. and Chris, and everyone.
I think I only wanted a shoulder to cry on.
I know what I need to do and, like mambo, I have delayed too long. I know the business enough to know the likely problems. I know it is a risk. It hurts the most that I will be losing so many friends. The studio where I danced was like home to me. It is my wish to make the parting as friendly and professional as possible, and I think my coach would respond in kind, but who am I kidding? With the gossip-mongering that is so much a characteristic of our little world, that will be some act to carry out.
Right now I feel like an orphan.

I hope I didn't sound too cavalier about your situation...studios can create really nice social circles that are comfortable and fun to be a part of. All I can say is that in my time people have come and gone and moved to different studios and that the ones who I really was friendly with still are friendly, and the ones who really were my friends definitely still are. It's not as bad as changing high schools, that's for sure!

I recently let go one of my three instructors. While I agree with the poster who said it's not really a "break up" since it's a business arrangement. However, there's still a certain amount of emotion involved if you are friendly with your instructor and have been with him/her for a long time. Our partnership lasted seven years and I learned a lot from him. However, economic considerations and a desire for a fresh perspective (mostly economic considerations--I was broke!) made it necessary to move on. It was a difficult decision and I held on as long as I could because he is a great "all-round" dancer and really good about technical issues. I never had romantic feelings toward him, but after a few years you do get comfortable. Anyway, when I told him I was having trouble financially, he even gave me several hours for free. I let him know that as much as I appreciated his efforts to help me continue dancing with him, I'd have to stop working with him within a certain timeframe. It wasn't going to be a surprise to him. I didn't tell him that I also wanted to get a fresh perspective and that I needed to get out of debt to do so. As with quitting a job, it's sometimes a good idea to keep in touch and not burn your bridges completely. I intend to do this through his weekly technique class which is more my speed financially at this time. This instructor was very understanding and wished me the best when we parted. I intend to refer new people to him and I never hesitate to mention the role he has played in developing my skills. I spent the last seven years with my guy, and it was a very important relationship, but fortunately it doesn't hurt a lot.

Decide do you really want to leave your teacher.
Could you work things out with a straight talk?
Would a Months break help?

Identify what is going wrong, is there a solution? a compromise?

I can only speak from a coaches point of view, often the teacher puts a lot of work into the pupil, produces a high quality, creates something he is proud of.
Gives a student something for life then suddenly she goes...
It can be as bad for both sides.
Try to find an ammicable solution before taking the drastic route

While I agree that it is a business relationship, with all due respect, changing teachers is not comparable to changing grocery stores.

I realized after I changed that I had delayed too long before doing so.

I hope your change goes smoothly. I tried to leave in a civil way. I told my former teacher I was leaving before I told anyone else and before I approached a potential new teacher. Nevertheless, my former teacher didn't speak to me for more than a year after I left. This, of course, just reinforced the decision I had made.

I agree with Ian and I really respect Chel's candor and integrity of speaking with her former teacher before telling anyone else. One thing I would add is that an open dialogue with one's teacher/coach before leaving would be a good way to start. If one is unhappy with their teacher/coach for some reason, then why not express it before deciding to "shop around" or leave? It could be that the teacher/coach may not be aware of any problems -- after all most teachers/coaches have several students and try as they might, they can't always know exactly what each one is thinking/feeling all of the time.

If during that conversation you see that the teacher/coach is getting defensive or becoming hostile at the idea of your leaving, then it may be time for a change. If you feel you've outgrown your teacher and he/she agrees then it could very well be that your teacher/coach can assist you in finding the next best teacher/coach for you.

Open dialogue is key. Please know that I didn't say it would always work, sometimes dealing with artistic folks feelings can get hurt and some people do tend to hold a grudge etc (see Chel's post) but at least as a student you've done everything you can to end the partnership/business relationship amicably (SP?)