Joshua Jackson) and Olivia (Anna Torv)...are assisted by an eccentric scientist/mental patient (John Noble), and the frame story is about parallel worlds, not aliens.
It was produced by J.J. Abrams, who helped eliminate almost all gay people from Lost, so you have to expect even more heterosexism than usual in sci fi series. And, indeed, people are always blathering on about "my husband!" or "my wife!", mourning lost heterosexual loves, and assuming universal heterosexual identity. When Fringe first aired in 2008, I refused to watch because the pilot hit you over the head with "we're all heterosexual! we're all heterosexual!" in the very first scene.
But I have noticed something interesting. In every episode, at least one of the guest stars is buffed. Body by Michelangelo, Like, built.
1, "A New Day in the Old Town": Olivia has an auto accident and disappears for 40 minutes into a parallel world. Luke Goss of Hellboy as "regular guy" Lloyd Parr.
2. "Momentum Deferred": Shapeshifters from the parallel world appear to steal cryogenically-frozen heads while talking about their wives. Sebastian Roche (left) as Thomas Jerome Newton, aka Omega Man, a buffed villain from the Other Side.
4. "Snakehead": Drug dealers are smuggling parasitic organisms into the U.S., using the bodies of Asian men (and their wives and children) as hosts. They need to show the parasitic organism moving around inside the bodies, so lots of hunky Asian men take their shirts off, notably former model Jack Yang.
6. "Johari Window." See, there's a town full of deformed people who look normal most of the time, and don't like outsiders. Including a heterosexual nuclear family, with the dad/husband played by bulgeworthy Canadian hunk Martin Cummins (left).
7. "What Lies Below": A 13,000 year old virus that wiped out all of the Pleistocene mammals resurfaces in an office building. One of the quarantined office drones desperately calling his wife is played by Al Miro (left)
8. "Jacksonville": A building from the parallel world appears here, merging the bodies of two guys. The one desperately calling for his wife is played by the extremely cute Ryan McDonald.
9. "Olivia in the Lab with the Revolver." An illness from the parallel world shows up here, with muscular actor Jamie Switch as one of the victims.
11. "White Tulip": A scientist tries to go back in time to reunite with his dead fiance. Jackson Berlin of Man of Steel plays Agent #2 (left).
And that's just Season 2.
I can imagine the conversation in Casting: "Ok, your character is a businessman who explodes on the subway after yelling for his wife. So take off your clothes...."
See: Prime-time Dramas Think You Don't Exist; 15 More Beefcake Stars of Fringe. and The Top 10 Hunks of "Orange is the New Black"