Being reminded that Ryan Guzman and Tyler Hoechlin were roommates once has me thinking...
What if instead of El Paso, the Diazes lived in Smallville, Kansas.
And while Shannon was still Eddieās first girlfriend, his first relationship was with farmboy Clark Kent.
Of course they don't last, Clark moves to Metropolis, Eddie moves to LA.
One day, when Eddie goes back to Smallville with Chris, and Buck tags along, Clark happens to be there visiting his folks as well. And perhaps Eddie, perhaps Clark, drops that Eddie and Clark used to date.
And this sets Buck's jealousy off.
It's pretty embarrassing, especially because Clark does not realize what Buck is trying to do at all.
However it all comes to an end when Buck finds out that Clark is also Superman.
("You're telling me that you and Superman used to date?" "No... me and Superboy. He was too young to be Superman.")
Buck gives up. He finds Clark and gives him the "you win" speech only for Clark to tell him:
2) Eddie is so very obviously in love with Buck
Buck is too stunned to believe him, until Lois arrives - finally - and introduces herself to Buck.
Clark gives Buck a pep talk and soon Buck is off to confess his feelings for Eddie.
Epilogue Buck and Eddie and Lois and Clark are eating at a local diner enjoying each other's company when Clark gets an alert and has to dip, leaving Lois with Buck and Eddie. "He does this often?"
Lois, "Yep." Eddie, "You have no idea."