I just see a whole lot that can go wrong here.
The main thing, tension or not, is the student/teacher relationship. That is the sort of mistake that could be career ending for him if someone were to find out. Either wait until you are finished with that school, or find someone else. Even if you were to wait until after you finished the course, while still attending that school, he would be branded "the guy who fucks students", and have a very difficult time afterwards.
I'm not going to comment on your relationship. If that is something you both allow, or you are looking to go outside your relationship, that choice is yours alone to make, and perhaps a matter for your conscience.