Going to turn this into a fic at some point but: Steve starts getting weird leading up to his first anniversary with Eddie. He's distant one moment, then all over Eddie even more than usual the next. It takes Eddie a little while to notice and then, when he does, and he looks at the calendar, the dots start connecting. It's been nearly a year since they got together and Steve is acting weird. That can’t be good. He asks Dustin and Robin and some of the others if they've noticed Steve being weird lately, but no one has. It's just with Eddie.
The only conclusion Eddie can come to is that Steve is having second thoughts about them and if he is then...Steve can tell him himself, damn it!
Only, Eddie doesn't want to ask because he's not sure he wants to know. But then not knowing is worse. So, he asks. But he doesn't ask Steve because he's not that brave. He talks to Robin. He tells her what's been happening and how their anniversary is coming up and it takes Robin a minute to make the connection but then she says, "You know that he and Nance broke up just before they officially got to a year," and then the dots really connect. For real this time. And Eddie feels like kind of an asshole for thinking...
He thanks Robin and he doesn't say anything to Steve but he's extra affectionate, trying to reassure Steve without saying anything as their anniversary draws closer. He’s not sure it works but Steve seems a little more at ease.
And when the clock ticks over to one minute past midnight on their anniversary, Eddie wakes Steve up. Steve is grumpy at first, and then worried that something's wrong, until Eddie says, "Happy anniversary."
"It's officially one year since we got together." Eddie smiles softly. "We made it."
Steve smiles back and says, "You couldn't have told me in the morning?" even as he reaches for Eddie.
“Couldn’t wait,” Eddie says and kisses Steve and holds him tight.
And Eddie does the same thing every year for many many years to come.