You have a somewhat complex issue that needs to be addressed by a competent family law attorney. Once that attorney has a full appraisal of your situation, you can be given the proper advice on this issue.
With that said, you can file for divorce (or legal separation) whenever you choose. The only real way to keep assets from disappearing is to file.
Nothing in this communication should be considered legal advice. Nor should this communication lead you to believe that an attorney-client relationship has been created. Only after thorough analysis of your case with you in my office can I provide effective legal advice on your specific issue.