Legal Question in Real Estate Law in California

If he will sign a quitclaim deed you can. If not, you've got a real problem. You MIGHT be able to as part of a divorce proceeding, maybe. You MIGHT be able to prevail in a quiet title action, but you have not given any facts so far that would support that.

Whether he would quitclaim his interest back to you may depend upon whether there is significant equity in the property. If he is not "on the loan" and there is little or no equity, he might be convinced. That would be a matter of personal persuasion as much as a legal issue. However, since you apparently bought 15+ years ago, there's probably a lot of equity which he may not give up readily.

There would be two ways to prevail in a quiet-title action: by winning, or by the suit encouraging him to quitclaim to avoid the entanglement in a lawsuit. You don't seem to have grounds for quieting title, but there is a slim chance worth investigating, in that the Family Code requires a transfer of real property between spouses to be done with clear intent to make a gift - sometimes the deed itself is clear evidence, sometimes not, and a good family-law attorney could review everything in writing and tell you whether there is a valid transmutation (as such transfers are called) or whether it could be attacked in court.