He is not liable if he didn't co-sign.
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Actually, I believe he probably is. Washington, as you know, is a community property state. Thus any debt you enter into will be presumed to be for the benefit of the community, meaning both of you. As you entered into a debt to assist your daughter, there is a presumption that this benefits both of you. Now, this is only a presumption, and there are ways to overcome that presumption, and there may be facts here that make that presumption untrue, but until he can overcome that presumption I would presume he is also liable.
Check with your divorce attorney to see what he/she thinks about this. They should know enough about your situation to give you an informed opinion as to whether he (your soon to be ex) is liable for this debt.
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