In one word: No. Property acquired before marriage, or that is received from inheritance or gift, is characterized as “separate property,” but that character does not make that property untouchable in divorce. 
Similarly, while Washington is a community property state (community property is what you or your spouse acquired during marriage from labor), the court is not limited to dividing only community property in divorce. In a Washington divorce, if you were to go to court and have a judge make the decision for you, the court will take divide both community property and separate property, and divide both in a manner that the court finds just an equitable. The court may try to award separate property to the person in whose name it is titled but will not do so if that does not lead to a just and equitable outcome in the judge’s view. Hence, it is not uncommon following trial for a judge to say that some (or, rarely, even all) of one person’s separate property gets awarded to the other person if that’s what would result in a just and equitable outcome. When you reach an agreement between yourselves, you may or may not choose to use a similar approach.