Omar Sy is 43. I find him magnetic to watch onscreen, but I’ve never seen him outside a film or television series.
Eva Green is the sexiest woman of any age, period.
I just realized that SIMON HELBERG is now 40yo. Step to the head of the line, Simon! 
Thank you @mordecaiB!
I will have to admit, as a straight male, that my two choices, Nikolaj Coster-Waldau and Daniel Craig have been on the list when I first saw 'em, but have since aged out of the OP’s criteria. I could see the “Jack Ryan” John Krasinzki, but unfortunately can’t unsee the “Jim Halpert.”
I second @What_Exit with Amy Adams.
Tripler
I have a soft spot for redhead gals.
He is no longer in his 40’s but this clip of Jamie Foxx on the Graham Norton Show I think is relevant (he was 49 at the time), or at least amusing:
//i\\
Well, Stacey Dash is too old at 54, even though she still looks like she’s in her 30s.
Lisa Bonet is 53.
But Shanola Hampton is a beautiful black woman at 43.
Sure, he’s in his 40s.
Kinda violates the spirit of the thread. Speaking as the OP, I know there are sexy 50-somethings. And 30-somethings. And 60-somethings. They’re possibly even sexier than any 40-somethings you can think of. But this thread is for 40-somethings. Can we stick with that here?
Sofia’s 48 (a few months older than me). She’s still got a year and change until she’s in her fifties!.
Jessica Alba, Natalie Portman, and Anna Kournikova are all a couple months shy of 40 now…
For the ladies, I understand Tom Hiddleston(40) and Joseph Gordon-Levitt(40) check a lot of boxes.
I have to agree with this sentiment about Momoa. I mean, I’m straight, not blind.
Interesting. I’m gay, and he does NOTHING for me.
He doesn’t qualify for this thread, but what about Chris Hemsworth? Ay caramba!
You wouldn’t believe me.
Thanks @mordecaiB ! I don’t recall your name from before my hiatus, but I’m sure you’re sexy as hell too!
Oh, and I am an actor! I’ve been acting in student films and other no-budget local movies for about two years now. I’m the go-to “depressed middle aged guy” for the local university film programs.
Hey! I remember you in that one part! You did great!
Yep! I’m the guy in that thing!
Wait - are you the guy with the face who was in that thing with that other guy? Because that was awesome!
Stacy Dash and Lisa Bonet are attractive certainly, but for me, eh.
Shanola Hampton though, oh! Oh my, yes, she is most certainly attractive and sexy.
Somebody already mentioned Sofia Vergara, I’d add Michelle Rodriguez, Eva Mendes, and Rosario Dawson. I seem to be more attracted to the latin ladies.
I’ve always thought Tom Hiddleston was a good looking guy.
Holy cannolli, Tom Hiddleston is 40 already??! Why it was just last week that he was that breakout new young star in Thor.
Tommy from 3rd Rock From the Sun is 40? I don’t find this thread offensive, it just makes me feel old.
I kinda have a boner for J-Lo