Starbital, It sounds as if you are planning on telling your current students that you are opening your own studio. That could backfire & bite you in the booty if you do so.

I still advise for you to do blanket advertising, rather than directly solicit your current students. If they aren't happy there they will seek dance training elsewhere. If you have your advertising available in the area they will find you and come to you. Then your former SO cannot accuse you of directly soliciting her clients.