@May_Lily - I've never really had a "waifu" so I couldn't really give an example; however, if we're talking dating preferences (which is really what it all comes down to) then I'd pick a girl who is: kind, caring, honest, loyal, mature but playful, free thinker, emotionally open and patient, not afraid of being feminine, helps me to be the best version of myself without condemning my failings, loves herself, puts in effort and accepts my effort, a good sense of humor, doesn't like drama, etc. -- I could go on, but you get it. Obviously I'd want her to care about her body and try to look good, because I do the same as well. I don't care if she's smokin' hot, has big or small tits, or ass, as long as I feel the physical attraction as well. As for in bed, well... I'll just say I enjoy being in charge and leave it there.
As for people talking about "husbandos", it's a bit hard. I genuinely don't grasp the criteria women use to determine. I imagine it's much the same with some tweeks here and there. I will say that a lot of the male characters in manga are either incredibly soft, unassertive and dense, or they're goofballs who think exclusively with their dick. There's occasionally some who come across as more relatable, but more often than not I find a lot of them are side-characters, so we don't always get a good picture of who they are. I guess it depends on what you read as well, because likewise, a lot of the female characters can come off plain silly in their "devotion". There's also a large amount of cultural difference that makes it more difficult to really give feedback without sounding insulting -- if that makes sense.
It'd probably be best if some girls gave their feedback since it's clear I don't really get it lol. I guess the point is to simply find a character that you'd want to be with; if they were real. I don't think their marital or relationship status particularly matters -- it's just someone you'd immediately wife/husband up. Maybe I'm mistaken, though. For some it might mean something else entirely. I just wanted to give a hand since it seems only half your question was answered (waifu) and the other half is something that interests you, too.