Legal Question in Real Estate Law in California

I think so. This would be improper if you were still married and the property were community property, but after dissolution of marriage there is no longer a community and therefore no community property. Courts may also divide co-owned (joint tenancy or tenancy in common) property in a dissolution proceeding if requested to do so by either party. Your analysis needs to begin with what your marital settlement agreement or decree says about the division of assets. (I assume you have a final decree, not just termination of marital status).

Unless the decree of MSA says something to the contrary, after divorce each former spouse may deal with their property interests without the signature, or the knowledge, of the other. This includes putting their part interests in real property into trusts.

Please note that one co-owner can never dispose of the other co-owner's interest! Your ex-spouse can put his or her half ownership into a trust, or even sell it..... but CANNOT put the other half he or she doesn't own into the trust without permission.

It is rare for a co-owner to sell a part interest in real property because there is little or no demand for shared ownership with a stranger. That doesn't make it illegal.

All owners of record, on title, must sign to transfer property. However, he could put 'his' share in trust without you. If you actually believe your title interest has been improperly handled, you could seek cancellation or could sue if necessary. If that is the case, and you're serious about getting counsel to take action, feel free to contact me.