Washington will recognize a common law marriage only if the parties relocate to WA from a state that recognizes common law marriages, otherwise it will not. There is a newly emerging doctrine called 'committed intimate partnership' which can under certain circumstances provide for a distribution to a parter. It is unclear from your fact pattern whether or not this would apply in your circumstance or not. This would be a case to take to a local family law attorney for their opinion.
If you are being threatened, please contact the Domestic Violence office in your county's superior courthouse. You can ask the court to make him stay away from you and stop threatening you. This will not cost you anything, you simply have to ask. You can get relief very quickly, usually within a few hours of filing a petition for a DV protection order. DV orders are designed so that you can apply for one and get a hearing without having your own lawyer.
Hope this helps. Elizabeth Powell