Sakusa knew he shouldn't be with you, you knew you shouldn't be with him. But you're technically still together, it was an on and off relationship. Always coming back to each-other, you were his collar. The thing thats keeping him from running away.

It was obvious you two were meant for other people, but you both don't feel like you need another. That's just how it goes for you two, even with the dozens of times you both separated for 'good,' you still went back to him, he still went back to you. Both finding the other at each-others doorstep.