i would honestly be fine with any of those lmao if you want to we can say they dated and while they were dating (which can be for as long as you want to, idc how long), they got a job at the same bar and even after their break up they remained co-workers. we can say there is some sort of tension but that they are obviously still trying to remain friends since they were together for such a long period of time. i don't care if we go with the other options though, this is just something that came to mind!