I will never get over how well written the FMAB romances are because when I tell you that not once did anybody kiss onscreen (married couples included), the reaction is gonna be "no of course somebody kissed...OH WAIT SHOOT YOU'RE RIGHT"
and yet you could easily put multiple couples on a list of best written romances or at the very least, best at "show don't tell"
and I know fans will read way more into subtext than was ever intended but like. Royai man. They are the pinnacle of subtext and double entendre. "I will follow you even into hell if you ask" was in the context of ambition, not romance, but every supportive interaction they have strengthens their bond in the eyes of the audience. She is his queen piece on the chess board: she is one of his most formidable allies, but she is also the queen to his king in a romantic sense. And the way he freaking loses it when Lust is about to kill "his subordinate." And the way "sir"/"colonel" and "my subordinate"/"lieutenant" become terms of affection
EdWin is more obvious, partly because multiple adults tease Ed about it and partly because we love a good childhood friends trope, but there's so much more there. At first glance, their bickering can come off as the early era shounen couple (nagging wife+idiot husband who tells her not to worry about it), but the content of the bickering and the level of development they both have as individuals is what sets them apart. While Winry does nag Ed a lot, she does it out of genuine concern for his safety and pride in her automail engineering. Conversely, Ed brushes it off and snaps back at her a lot, but for one thing, he doesn't want her to worry and for another, he eventually shows that he truly does care about her feelings and safety and has the highest respect for her automail work. He wasn't called the Fullmetal Alchemist for nothing (which is kind of a pun in Japanese due to his prosthetics and his stubborn/steel personality). This kid was straight up impaled and on death's door and said "this is annoying. I can't make Winry cry so I guess I've got to get out of this somehow" and did.
I could go on for an even longer time than I already have with more couples but I'll just take one more second to mention that I can't think of a single married couple in FMAB that didn't absolutely adore each other (the Bradleys don't count and she adored him at least)
Tldr I am and always will be astounded by Arakawa's writing