Who are the people that appear as your top six on you FB timeline?

[Fay]

When you go to your FB profile, there's the six people at the top bar and six more lower down towards the left (larger icons).
I've heard that these people appear there because you interact with them most publicly.
However, this guy keeps popping up in the top six (smaller icon one at the top of profile page), and I do not interact with him on Facebook. I haven't talked to him for about 3 months now, he hasn't either. We had a thing but he decided to "Be friends" and I eventually told him off for treating me like FWB and that was that. We only have a few mutual friends and we don't even have one picture together up on FB either. I only visit his profile once every few weeks on average, not very often. But he usually comes up on "my top six". It'll shuffle a little but it's always the same people that come up.

Could it be possible that he's stalking me?