Before I breach the topic of husbandos and waifus, let me be clear. I am loyal to my hubby. He's the love of my life, and the only one who keeps me sane these days. But for many of us nerds or otaku, I would say the lines of 3D and 2D don't generally cross. I think of my friend who literally thirsts so hard over every cute video game girl he sees that we forced him to get some "go to horny jail *bonk*" emotes made. He may be like that with the 2D girls, but in reality, he's actually a real cool and polite dude who would be an absolute rockstar to a real, nice girl in his life (though he might still make thirsty jokes). So you single ladies, I know a guy, HMU.
Fair warning, this topic can go to some pretty intense levels, and I'm really only going to brush the top of it. The short of it is waifus and husbandos are 2D characters that people immensely like and would probably marry if they were real. Of course, it can be 3D characters as well but when I say 2D, I'm referring to fictional characters and not IRL (which I affectionately call 3D). Typically, the terms husbando and waifu are exclusively for anime nerds. Before you think this is rather strange and why would anyone like fictional characters so much that they would want to marry them, I'd say that this is not all that different from when someone coos over how hot a celebrity is or collecting movies/memorabilia of actors or actresses. Both certainly have different levels of intensity, but whether the person you like is a celebrity or a 2D character or whoever, it's clear that we like to attach ourselves to these fictional characters.
Casual fans would probably not quite understand the numerous fanfiction, fanart, and smut that exists of favorite characters. It's actually quite natural though to grow attached to characters when you're someone who immerses or invests themselves in the story. Sometimes it's these fictional characters who cheer us up, and they might be the only ones to do so. Especially as the pandemic has become a thing, more and more people find themselves alone and missing social interactions. One of the things we humans do is interact via storytelling which is in anime, movies, etc. So when that anime girl is an absolute cutie (maybe tsundere) or when that dashing boy saves the day with his charming smile, we can't help but grow fond of them. It wouldn't be quite right to say all anime fans are lonely, but we certainly can appreciate the joy (and other emotions) a character brings when we see them on screen.
Personally, I love to write my own stories which means, I love taking stories that have already been written and borrowing their characters to match up with my characters. For me, when I obsess over a character, I don't necessarily obsess over them romantically. It's more something where I create a different character to join the story or romance a certain character. This way I'm interacting with the storytelling and making it a bit personal.
The criteria for waifu or husbando differs from fan to fan though some characters are certainly beloved by all regardless of gender. For some it's not a big deal and it's whoever is cute or handsome or moe, and for others it's certain characteristics like personality or traits that make them top tier. In general though, these characters have to look attractive at the very least. A bit of mystery also tends to make a character popular like Satoru Gojo from Jujutsu Kaisen or Ban from Nanatsu no Taizai. I think 2B from Nier Automata (which comes to mind since I recently played the Nier rads in FFXIV) would fall into this category as well though she also has plenty of other attractive traits about her. Empathy or pity also is a great motivator for liking a character. Do they have a pitiful background or are they an innocent puppy you want to protect? More than likely, they're top tier waifu or husbando material.
Of course, some of us (like me) enjoy the less popular characters for various reasons. The way they might be suave even if they're a dick, or when they act like a dick but are actually quite charming... I have fantastic taste in anime men, I tell you. Whether you like the popular main character or the obscure side character who dies, we, fans, obsess over them and collect all the merch we can get our hands on.
How many anime figures line your shelves? Or are they in a box somewhere while you wait to move out so you can proudly display them somewhere? We collect the things we like. I think collecting materials has been a hobby for mankind since they pretty much existed. We in a America suffer the problems having goods imported and seeing merchandise that will never make it over here. Or if you're like me and you live in the slow Midwest who can never keep up on pop culture, then you're pretty doomed to shopping online on obscure sites to try to get your hands on anime goods. I can barely contain myself when I spot a rare anime figure or merchandise on the shelf of some pop culture or gaming store here since it's such a rare commodity. It's probably why my poor wallet suffers from spontaneous expenses. But I digress, whether you're on ebay, somewhere online, or shopping at a local store, it's still a great feeling to own a figure, keychain, sticker, or something with your favorite waifu/husbando slapped on it. One of my favorite types of merch though is when I see the character on some sort of TCG playing card, like Claude from Fire Emblem Three Houses on a Fire Emblem Cipher card. There's so many types of nerdy things to spend your money on and show off your obsession with the character.
Waifus and Husbandos
Do you have the same type of waifu or husbandos? Or do you freely love all of them? It's pretty fun to get into this topic with nerdy friends or people at anime cons. You can get some pretty heated discussions (all in good fun though, don't take it too seriously!) and learn about new characters or series that you've never heard of. In the anime realm, there's countless series to look forward to, and even more if you enjoy reading manga. More of then than not these days, I read the manga and am pleasantly surprised to see my favorite characters come to life in an anime shortly thereafter. Some of my husbandos below! Props to you if you see a pattern between them! Images all from their respective fandom wikis.