Legal Question in Wills and Trusts in California

No a spouse does not have to sign a living trust. If you do sign, then you are agreeing to its provisions and dsiposition of assets, inotherwords you have created a marital trust.

It is not clear what you mean by sign. Are they signing as trustor, setting up a trust, are they signing a waiver, or are they accepting a position as a trustee?

A married person may establish her own trust without the signature of her spouse (for her separate property, and in some cases for her share of community property.