The Marvel Cinematic Universe has a lot of catching up to do with their comic book roots. Over the course of 82 years, Marvel has managed to evolve their characters into their perfect forms. On the other hand, the MCU has often simplified aspects of certain characters, such as their sexuality. One character affected by this was Thor’s sibling Loki.
The MCU has previously treated sexuality as a mystery, even for openly LGBTQ+ comic characters. In the first episode of the Loki TV show, Marvel did reveal via a glance-and-you'll-miss-it form that the character was gender fluid. However, they had yet to reveal the character’s bisexuality... until today.
Loki is canonically bisexual
Loki's sexuality in both comics and Norse mythology has always labelled the character as bisexual. The character's never been especially fussed about the gender identity of any of their partners. For fans of the Marvel Cinematic Universe, this is finally confirmed.
Spoilers for Episode 3 ahead
In Episode 3 of the ongoing show, Loki teams up with Variant Sylvie to hijack a train. On the train, the two have a conversation about their various relationships. Sylvie explains that she maintained a multidimensional relationship with a postman. Our traditional Loki explains they've never felt tangible love.
When asked if, as a Prince, there were any Princesses or Princes, Loki replies: “A bit of both.” However, the character has yet to be in a “real" loving relationship.
The MCU has a way to go
The Marvel Cinematic Universe still has a way to go. In terms of character sexuality, multiple Marvel comics characters are openly LGBTQ+. Of course, Marvel is still slowly building their universe, so we likely won't see newer characters for a while.
However, the MCU will be respecting the original sexuality of already established characters going forward. For example, Thor: Love and Thunder will have an openly bisexual Valkyrie just like in the comics.