Disconnecting completely from this relative, as stated above, is an excellent decision. Most magic, in order to work, requires an avenue to reach its target. The fewer paths you give it to work, the less effective it will be and the longer it will take to achieve results. That goes for your own magic too. In other words, you should minimize potential paths connecting this enemy magician's magic with you and your husband, while maximizing the potential paths for your own magic to work defensively and hopefully reverse the damage already dealt.
This falls outside the scope of the occult, but if you have evidence this relative has been harassing you and your husband beyond simply a perceived magical attack, but as well as verbally and especially if physically, it would be wise to take this case to the police. Sometimes police are completely useless, and they will almost certainly laugh you off if you even breathe a word about magic to them. But if you have other forms of evidence you could vastly reduce this person's ability to interact with you at all, maybe even get them sent to prison, which would completely cut them off from their connection with the magician they are paying to harm you. That magician won't work for free, that much can be said, and his attacks will certainly cease.