hypotheticals if you're in the mood: Do you think if Eddie died (presumed dead because I am me and want the eventual happy ending) instead of shannon, would buck and shannon have had sex about it. IF shannon lived and they divirced would various buck ndes send eddie running back into shannon's arms (like buck getting back with taylor after eddie gets shot) and how much would she indulge this/even realize what was happening
if eddie died when shannon did, in mid season two, I think she and buck would meet once at the funeral and she would barely remember him, and buck would have a huge hole in his heart that never really healed even though he and eddie barely knew each other back then, and then a few months later chris and shannon would go to the pier on a saturday morning when a tsunami hit, and would wind up being rescued by this big guy who pulled them out of the water and onto the top of a fire engine, and chris would go BUCK and start sobbing, and the three of them would sit on top of the fire engine for long exhausting terrifying hours and then buck would go i, i, i i miss him, and shannon would think who the fuck is this to say that to me, and she'd be blinking raw tears out of her eyes and she would see the same expression on buck's face and she'd think to herself, who IS this man, and then the second wave hits and they'd lose chris and both of them would spend the next seven hours desperately searching for him, and when they found him finally at the triage center buck would be holding shannon up, and they'd grab onto chris together and sort of shudder like one grieving relieved body and then she'd show up at the firehouse a week later looking for him, to say thank you, but he wouldn't be there, because of the injury, but bobby would give her his number, and then she'd call him and they'd talk on the phone, first about the tsunami, then about chris, then about eddie, and she'd invite him out to ice cream with her and chris as a way to help chris heal, but one thing leads to another and they end up in bed, but it's basically terrible, because shannon's grieving her husband and buck is grieving his friend and also his whole life (lawsuit era), and they're still fundamentally just clutching onto each other in the middle of an emotional tsunami, trying not to drown.
(sorry i know you said you didn't want eddie to really be dead! in my defense i'm very tired.)
if eddie 'died' later on, after buck actually loved him, and after shannon got to know buck better, i think they could totally fuck right away, out of a much more urgent adrenaline-fueled fear. (I think this could absolutely happen when buck was in a relationship. put this near the shooting and instead of kissing lucy, you have buck sleeping with shannon, but then not telling taylor about it because...because...well, it was about eddie! it was a grief thing!) and then eddie comes back, and buck and shannon are both like !!!! WELP, time to pretend that never happened, even though eddie's still dating ana so it's not like buck and shannon COULDN'T sleep with each other (except that buck is still dating taylor. buck loves taylor. oh no, buck just asked taylor to move in. this will not end well for buck,) and eddie's alive and they're all happy about that, they're so so so happy. (so happy buck didn't tell eddie about the sleeping with his ex-wife thing. because! they were so happy! and eddie was recovering! and also buck's not telling taylor about it either, and. somehow it feels like the same lie?), and then shannon calls buck up, and she sounds weird on the phone, and he's like hey what's up you sound weird, and she's like if I tell you something you have to promise you won't tell eddie. and he's like wow okay, sounds bad. is it about chris? because i don't think i could lie to eddie about chris, and she's like no, no, it's not about chris. and he's like oh god is it about you? are you okay? are you dying? and she's like i'm not DYING. just promise me, and he goes okay okay fine i promise, and she says, voice taut as a wire, I'm late. and buck goes: for what? and she says, buck, jesus christ, i'm LATE, and buck—bluescreens. yeah, shannon says, sounding tired. i know.