Legal Question in Real Estate Law in California

First, please note that the term "separated" can have two entirely different meanings. One is "still married, but not living together," and the other is "legally separated by court decree and for most civil purposes the same as divorced." Since you refer to your "ex-husband," I'd be inclined to think you've been through the legal process in court. In that case, there is no longer a marital community and no community property, and no real need for a quitclaim. Almost all the same laws, rules and policies that apply to divorced couples also apply to legally-separated couples. On the other hand, if you don't have a court decree of legal separation, a quitclaim deed would be a good idea and may be required by a lender.

If you are still married, many title companies and escrow companies request the execution of a quit claim deed to ensure that the title they list as being separate property is truly the separate property of the party acquiring the property. It is legally erroneous, because a quit claim deed does not transfer after acquired title, but they use it as a matter of policy. Sort of an "everyone else is doing it wrong, so we should do it too."