I think love that we know colloquially is attachment which could easily transform into hate. For e,g.: If you put 2 ‘Ex lovers’ together and monitor their brain activity, even if there are 10 other people in the room, they would be giving each other at least 50% of their attention, partly subconsciously. Somehow, in my experience, even if I try hard not to, my attention is drawn towards the people I concentrate / have concentrated upon in the past.
So its like, you concentrate on the good things initially for a long period of time and your mind gets stuck with it and you subconscious begin to give much greater attention to this person. Once the breakup happens, you try to detach by trying to see only the ugly in the person which makes the relationship transform into hate. But you are still concentrating on the ugly. That’s what makes detachment paradoxical. Hate and love might just be the same thing. Maybe if we fully concentrate on something for whatever it is with full acceptance, that might be true love.
We all concentrate upon those things we love, and we love those things upon which we concentrate our minds. To detach is the skill that’ll prevent hate from happening and also free the attention for the next object/next moment. Plain observation without judgment I think is the only way to detach.