Detaching Spiritually From Someone

I am somehow Spiritually attached to someone whom I was romantically involved with. We stopped talking about a month ago and yet I dreamt about him and his ex recently. I got a bit snoopy and looked at his social media to find he was back with his ex, which I honestly did not expect. This isn't the first time this has happened with this person though. In fact, it's happened many times during the duration of me being involved with him.

My question is, how do I detach?

There are various techniques in (I think) the PSD forums- Or use the search function for "Ninja cord-cleaning" and the "Blue Room Method". I like the blue room method better but everyone visualizes differently.