Even though Namor has been part of the Marvel Universe since the 1930s, the Sub-Mariner remains its most eligible bachelor. Between his royal status and impressive beach body, the mutant known as Namor the Sub-Mariner is a catch by anyone's standards.
Recently, comics have confirmed that Namor's popularity isn't contained to the mainstream Marvel Universe. And the past few years have cemented him as one of the most desired partners across the Marvel Multiverse.
Namor and Emma Frost
Namor was Marvel's first mutant, but he didn't join the X-Men until he was enticed by Emma Frost. Their alliance was partially strategic. They were both members of Norman Osborn's Cabal during Dark Reign and were briefly members of his Dark X-Men team. It was in their best interest to form an alliance against the rest of Osborn's inner circle. There was also an obvious and longstanding mutual attraction between them going back to her time with the Hellfire Club.
Namor was open about his interest in Frost during his time with the X-Men, even though Frost was involved with Cyclops at the time. Frost was open with Cyclops about her history with Namor and he trusted her to remain faithful to him. Instead of reassuring Frost, that faith pushed her into Namor's arms, as Cyclops never showed the passion for her that he did for Jean Grey.
Their relationship took a dark turn when they were both empowered, and twisted, by the Phoenix Force during Brian Michael Bendis and John Romita Jr.'s Avengers vs. X-Men. Going behind Cyclops' back, Frost tipped Namor off that the Avengers were hiding in Wakanda. Namor flooded the kingdom, an act of aggression that led to a long-term feud between Namor and Black Panther.
Namor and Power Princess
One of the many variants of Power Princess was part of a plot to murder Namor in the mainstream Marvel Universe. The Power Princess currently appearing in Heroes Reborn has a more tender relationship with the Namor of her reality. He's one of the few major Marvel characters who hasn't been left dead or worse after encountering her.
During a brief moment in Heroes Reborn #6, by Jason Aaron and Erica D'Urso, Power Princess contemplates curing her boredom by calling her teammate Hyperion. She reconsiders when she realizes it would mean listening to him talk about things that she doesn't care about. It makes her nostalgic for her past with Namor. In a rare sentimental moment, she thinks "You simply haven't lived until you've made love on the seafloor while sharks feed on the Nazis you've just torn to pieces."
Namor and the Enchantress
Recently in Kelly Thompson and Lee Garbett's Captain Marvel, Carol Danvers found herself in a dystopian future. The only livable part of the surface world was ruled by Ove, the son of Namor and the Asgardian Amora The Enchantress. Ove put on a benevolent front in his utopian kingdom, hiding the fact that it was powered by enslaved superheroes like Magik.
The Enchantress later told Danvers that Ove inherited the best and worst traits of parents with villainous pasts. Beyond his desire to rule, which included a time travel scheme, Ove also inherited his father's occasionally lethal tendencies. Ove claimed Namor had been assassinated by revolutionaries. He was actually murdered by a teenage Ove, causing his mother to flee with him to the surface.
Namor and the Invisible Woman
The attraction between Namor and Sue Storm Richards has existed since their first encounter in Stan Lee and Jack Kirby's Fantastic Four #4. While she isn't immune to his charms, the mainstream Marvel Universe version of Storm has never succumbed to them completely. She's remained faithfully married to her Fantastic Four teammate, Reed Richards, for years in spite of the fact that Namor would make her the Queen of Atlantis. That's not to say that Reed doesn't consider their relationship inappropriate, even when she's just asking for his help in battle.
Namor and Sue have gotten together in many alternate realities, and even if they've never truly gotten together in the Marvel Universe, the Fantastic Four hero is still one of Namor's most famous partners.