On a commercial lease, is the spouse of lessee required to sign the lease? I am being strongarmed into it and want nothing to do with his business.

There is no law requiring a spouse to sign a lease of any kind.  This may be required by the landlord as a condition to agreeing to lease the property.  That's entirely appropriate and quite common.  I'm not saying its either fair or adviseable.  if you won't sign, the landlord might simply decide to not lease the property.  The proposed tenant can try to offer the landlord some other type of "security" such as pre-payment for some portion of the lease, a pledge of other assets, etc.