who is the really handsome guy they keep showing?

it's meeeeeeee!

Mariana, they keep showing a young-ish man (in his mid to late 20's) in a black jacket and black hair watching/spying on Jack (and whoever he is with in a scene). they've shown him at least 2 maybe 3 different times. it's just odd that with 3 eps left to this season there's no mention of who he is. but then again there's hardly any storyline/plot going on on this show.

There is this guy who seems to be watching or following Jack. I wouldn't be able to rewatch all the episodes now to tell you the exact scenes, but in episode 4 they showed him at 6 minutes 15 seconds in, watching Jack and Gary as they were walking towards that building Cranfield left in a trust.

I think they purposely cast someone very good-looking because if it were someone nondescript, people wouldn't notice him in the scene.

I don't believe he was in the last episode, though (unless I missed it?..), but they showed him for a few seconds in every episode prior.