Sometimes the people we reach out to can't cope with our problems. It's not necessarily about you. It's about the other person. It could be that the rage your cousin saw was the limit of what they can endure.
Don't give up on your cousin and don't give up on you. No doubt you were left with bruises and scars from the treatment you got/get from your husband. Have you sought any help from a therapist? I think it would be invaluable.
In the meantime, we're here to listen and offer any help that we can.
Please take care of you.
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.