While you can’t force him to take lessons you can explain how important it is to you and hopefully he’ll agree. If he won’t see if you can make a deal. Is there something he really wants for the wedding, your honeymoon, home? Would you be wiling to give in on that issue if he agrees to take the lessons?
Also, find out why he’s adverse to it and maybe you can work around the issue. If he feels uncomfortable in a class environment opt for private lessons. Maybe he’d be more comfortable with a certain dance style.
You can also talk to the dance school to see if they have any ideas -- you’re not the first bride to have this issue.