The only part your husband has to sign is the page where he waives his homestead rights to the property. If he refuses to do this, you cannot get the loan. This is because without the waiver your husband could prevent the bank from foreclosing on the property even if you don't make the mortgage payments.
Your husband is not signing the Note. The Note is the only document that makes him personally liable on the loan. So long as he does not sign the Note then he cannot be held personally liable on the loan.
The bank needs your husband's waiver of homestead rights or they absolutely will not refinance your loan. There is no way around this requirement. If the refinance is of benefit to you, you need to convince your husband to consult an attorney and satisfy himself that he can sign the deed of trust.
You can reach Harkess & Salter LLC at (303) 531-5380 or info@Harkess-Salter.com. Stephen Harkess is an attorney licensed in the state and federal courts of Colorado. This answer is for general information only and does not create an attorney client relationship between Stephen Harkess or Harkess & Salter LLC and any person. You should schedule a consultation with an attorney to discuss the specifics of your legal issues.
I agree with Mr. Harkess and add that the lender only needs the Deed of Trust signed because you and your husband could mutually agree to void your prenuptial agreement in the future. If this happened, and one of you later sought a divorce, your husband would have a statutory interest in the property until resolved in the divorce. This potential requires his signature.