Ant-Man and The Wasp: Quantumania revealed that Janet wasn't alone when she was trapped in the Quantum Realm for many years. Instead, she was accompanied by Jonathan Majors' Kang the Conqueror, who was more sinister than she realized.
The pair worked together to repair Kang's time chair so they could escape the Quantum Realm, but after Janet learned of all the Conqueror had done in other timelines, she sabotaged it and trapped him down there.
MCU fans recently theorized that there is no way Janet and Kang could have spent so much time together and not have something between them. It was revealed in the film that Janet was involved with Bill Murray's Lord Krylar, and Janet explained her reasoning for that was she "had needs" while she was away from Hank. According to Quantumania's writer, the theories about Janet and Kang could be true.
Potential Romance Between Janet & Kang
In a recent interview with IGN, Ant-Man and The Wasp: Quantumania writer Jeff Loveness was asked about the possibility of Janet Van Dyne and Kang the Conqueror being in some sort of relationship while they were in the Quantum Realm for so long.
Loveness talked about how Janet would have had to be around Kang all the time, who he referred to as "Mr. Hunk," and alluded that it would be hard for them not to want to be with one another:
"Ohhhhhh. I mean, yeah you got Mr. Hunk over there all day, so mysterious. He’s got his little orb. I mean, I don’t know what’s in that orb."
The writer then went on to say that "(he) intentionally left it a little vague" when it came to a potential relationship because "there's a magic" in just implying certain aspects of stories rather than coming out and showing the audience. However, he did tease that the characters were "very good friends:"
"I intentionally left it a little vague, but clearly – let’s say they’re very good friends [laughs]. And I think sometimes we’re in kind of this YouTube reaction video world where everyone wants every little detail explained. And I don’t think I ascribe to that. I think there’s a magic in what is unsaid and what is not explicitly said."
Loveness also said that some things in film happen because they just happen, and every detail doesn't have to have a backstory or explanation. He used The Wizard of Oz as an example, specifically talking about how "the wicked witch of the west" melted because of water:
"And sometimes the wicked witch of the west can melt because water melts her. That’s like, that’s all you got to know, man. There’s no setup. There’s no foreshadowing. It’s like, yeah, you know what? Throw some water on her. And she’s gone. No offense to 80% of IGN’s audience, of which I am one, but chill out guys."
Loveness went on to talk a little more about the potential sexual relationship between Janet and Kang, specifically mentioning "novels [that] are sexually repressed" and how "there's a lot of strength" in "relationships that could go either way:"
"I love Jane Austen novels or English novels [that] are very sexually repressed. I’m sexually repressed. But I think there’s a lot of strength in those types of relationships that could go either way. And maybe it did, maybe it didn’t."
The writer also explained why Janet might have kept her relationship with Kang a secret from her family and cited multiple instances where telling them could cause bad things to happen:
"Maybe that’s a reason she didn’t want to tell her family about it. That’s part of it. And maybe she didn’t want to tell the family or the Avengers about it, because if they went down there, he would fuckin’ kill them. Or he would get their Pym Particles and get out."
Loveness compared the situation as a whole to "your grandpa talking about what happened" when he was away in the war. However, he ended by teasing that a sexual relationship between the two characters is possible:
"It’s something that, it’s like your grandpa talking about what happened to him in the Pacific Theater in 1944. Best not to bring it up. And because if you bring it up, it’s going to hurt a lot more people. But yeah, maybe they had sex. Who knows?"
Was Janet Romantically Involved With Kang in Ant-Man 3?
Before the release of Ant-Man and The Wasp: Quantumania, Michelle Pfeiffer revealed that Janet had a "very rich history with Kang" while she was in the Quantum Realm and also that "the Quantum Realm can change a person." The film itself showed just how much time Janet spent with Kang, and as Loveness said, it isn't explicitly stated if the two were romantically involved or not.
It was confirmed that Janet was with Krygar for at least a little while she was a part of the Freedom Fighters, and since she told Hank that she "had needs," it is reasonable to theorize that she and Kang may have got together.
Obviously, after seeing all that he did to other universes and timelines, admitting that she was with him wouldn't be something a character like Janet would be proud of, so she probably would want to keep something like that a secret.
Ant-Man and The Wasp: Quantumania is currently in theaters worldwide.