Coworker makes a noise that drives me insane. Should I say something?

So I have a coworker that sits across from me who’s a super cool dude, and we’re good friends and all – problem is he sighs non-friggin-stop, and the way he does it gets under my skin and drives me up the wall.

Usually I’m able to ignore it by listening to music, but there’s some days where it gets on my nerves way more than others. Should I find new ways to cope, or should I ask him if he could try sighing less? I just don’t want to be a dickhead ‘cuz I’m sure its his way of managing stress.