Okay I had a brain blast about Buddie last night and thought about it for a day and had to vomit it out so here you go, its long and I don't know how to do the "below the cut" thing, sorry for the long scroll.
Buck wants to be needed, not just wanted. When Buck was created it was because his body was needed, Buck himself wasn't wanted. After that need was unsuccessfully fulfilled, he wasn’t wanted or needed by his parents. Eventually, he found that he was wanted… but for his body yet again. Still, he worked with that, with meaningless moments of physical intimacy, of being wanted, but never needed. Even after his experiences in season 1 prompted him to morph into Buck 2.0, to seek out actual relationships with meaning and commitment and wanting to be someone that his partner could lean on, that his partner needed, he kept on ending up in relationships and flings where he was wanted (yet again for his body primarily) but not really ever needed. Literally every single relationship. Abby wanted Buck because he was hot and cute and kind, but ultimately needed to find herself and didn't need Buck for that. The relationship with Ali ended too fast for anything deeper to develop. Taylor's her own beast and their relationship changed over time but even when she arguably could have been percieved to have needed Buck, during the time when her father got put up for parole, she handles it on her own and kinda accepts Bucks emotional support but clearly doesn't need it. Natalia wants Buck because she finds him interesting, she doesn't need him. In his relationship with Tommy it's really more Buck who leans on Tommy as he adjusts to his newly discovered bisexuality, but it was more because Tommy's a guy and not because the guy was Tommy. Even though the relationship lasted several months, they never developed the kind of partnership where they leaned on each other (let's be real, that's because Buck already has that kind of relationship with Eddie). In other words... Tommy didn't need Buck. It's heartbreaking honestly, watching this cycle happen again and again given that we've known since season 1 exactly what Buck wants which is a real relationship where his partner truly sees him and trusts him and respects him and needs him, he literally just wants to be a husband so bad.
Eddie on the other hand needs to be wanted, not needed. Eddie’s sisters and mom and dad needed him to step up and “be the man of the house”. Honestly, based on how his parents treat him as an adult, I doubt that he ever felt wanted as a kid. He did step up, did what he needed to do for the people that needed him, but he’s not admired or respected for it by the people he did it for. Helena especially is ever critical of him. So, not only was Eddie needed, he was needed and told that he was failing at it. This theme is repeated with Shannon. We don’t get to see their early romance/relationship, and of course there must have been attraction and connection, but their relationship became defined by the pregnancy. Once again, at 19, Eddie is needed. He needs to be a man, a father, a husband, to provide, to support his wife and child. And yet again, he fails or at least believes that he does. He isn’t a good partner to Shannon even if he’s giving his all to meeting her and Christopher’s financial needs. For the first years of Chris’s life, he’s not really the father Chris needs him to be because he’s not there. Then there’s the failure of his and Shannon’s marriage which means he’s not being who and what Catholic culture needs him to be, a husband. And the nail in the coffin, years later after everything with Shannon and his grief and Kim, he hurts Chris and Chris doesn’t want him to be his dad anymore. Eventually, Eddie is able to bridge that gap with his son but only partly, only because he steps in to be Chris’s father again (not that he ever really stopped of course) because Chris needs him to. His whole life, in all the most important aspects, Eddie is defined by people needing him. His parents/sisters, Shannon, Chris, soldiers, the people he saves as a firefighter. Eddie is defined by his service and his failures. I think what he needs is to allow himself to have his own needs for once. And I think he needs to be wanted for who he is by someone who sees him beyond what he can do.
And the thing is, Buck and Eddie already are these things for each other. Naturally and easily, Eddie allows Buck into his and Chris’s life as a pillar of support. Eddie needs Bucks help, and honestly to be his partner (examples include Buck connecting him with Carla, asking for Buck’s help multiple times in communicating with or raising Christopher, Eddie being so pissed off with Buck during the lawsuit because Buck wasn’t there to support him when he needed him, Chris calling Buck for help when Eddie breaks down, Buck saving Eddie’s life when he’s shot, so on and so forth). And Buck, fuck does he want Eddie. On so many levels and in so many different ways. Of course there’s all the little hints that Buck wants Eddie like that but I don’t even really want to count them here because he’s clearly repressing it so hard it doesn’t feel like concrete evidence at this point in canon for their actual relationship (except I do have to make the honorable mention of “I don’t have to want to sleep with everyone I have feelings for” like okay you don’t have to but DO YOU??). Instead let’s just highlight that Buck always wants Eddie around, like there’s a million examples of this from “I’m in” for that gross drink Eddie described, being jealous over other people taking Eddie’s time/attention, getting excited when he thinks that Eddie broke up with Marisol because yay more hanging out time for Buck, and a bajillion other examples. And, crucially, Buck doesn’t actually need Eddie. He just wants Eddie so bad it seems like he does. We’ve seen Buck without Eddie and he’s clearly miserable but its not because he needs Eddie, needs Eddie to be of service, it's because Buck just wants him around all the time forever. I think the only real exceptions to this are like, life or death situations like 9x13 or Bucks recovery when he needed everyone’s support.
Anyways, they fit together like perfect puzzle pieces and I just think it would be so much more gratifying if they were able to recognize these things within themselves and each other and to allow themselves to be there for each other completely as partners who also kiss and say I love you.
Also final note I have to make honorable mentions about Maddie, Tia Pepa, and Abuela and their roles as the people who didn’t directly raise Buck or Eddie who did love them unconditionally, who didn’t contribute to these core wounds.