Hi there Petite. I am a male dance instructor, and I teach a number of couples. I would almost not even consider teaching a wife of a dancing couple without the husband being very interested in me doing that. If I do dance with a wife, while I'm teaching the couple, I always am doing so in instructing him (or at least I ensure he's at least 50% of my focus). And I always ask first (him), before I dance with her.
I have a few suggestions: since it is so hard to determine if you husband is justified in feeling a bit jealous (is he jealous of you and your instructor being together, or your dancing growing faster than perhaps his is?), or if your male instructor is physically attracted to you, I would recommend two things:
1) can you arrange that you and your husband take lessons, with each of your individual instructors, at the same time, in the same room?
2) Don't just take "coaching" lessons from the same man...there are a lot of good teachers out there...rotating who teaches you might help your husband's feelings, ... if he still remains jealous, there may be something in between you and he worth focusing time and energy on, or perhaps he feels like his teacher isn't giving him what he wants...talking to him about why he feels jealous would be my first step.
3) Why did you and he decide to dance? Most couples do to build intimace and to have fun! Perhaps revisiting these original goals would be helpful.
Hope this helps...happy dancing! :)