Well, you could do a 'bond' breaking ritual :)
I made one a while ago, due to a similar circumstance.
What I did was put to candles out.One to represent me, and one to represent the other person. I ties a thread to each of the candles, connecting them. Then, I lit them, and affirmed who they represented/ You can carve their name and yours into the candles if you'd like.
Then, I lit the candles. If you would like, you can do something like a banishing chant to empower the spell, but it really is up to you. Something like
"With this blade I now sever
all our ties now and forever."
Should work. Cut the thread and imagine the person leaving your life. Something more powerful could be used, but this worked for me :)
You can add herbs, colors, and all sorts of things to make it fit your specific situation as well. Good luck!