If it's just residual feelings that are present but non-intrusive, that should fade with time. If they're active intrusive yearning, you may have to consciously re-direct your energy into something else.
A classic breakup thing is to re-invent onesself, and while that may happen for a number of reasons, one of them is definitely the re-direction of previously outpouring care and attention back to oneself.
If you wanna do something kind of experimental to start understanding the nature of your attachment to this person, so you may eventually start separating from them, ask yourself what they brought to the table symbolically or practically. (Think 'they gave me a purpose' or 'they brought me closer to another aspect of life that I enjoyed' ect.) If you find anything that you may be able to get elsewhere, you can try and move yourself yourself in that direction.