Well, I suppose you can say that “pre-existing addictions can” make it impossible for a person to consent or can have an impact on a person such that his/her consent is somehow not marital. Yet, it is not a necessary result.
As far as a how a marriage can be invalid due to “defective consent”, there are many ways. I could lay them all out but don’t think that would really help. Would any of them apply in your case? I don’t know.
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