"The trouble is, you think you have time." - Buddha
I. There's still time.
He always sought him out in the mess with every step closer they got to stopping Saren. Asked his opinion on the mission, and asked about him. Kaidan had told Shepard... not secrets, but things he'd never told opened up to anyone about before. Things Shepard could have found out for himself had he chosen to - except he hadn't. He chose to learn only what Kaidan was willing to share. Shepard spoke to the others, too, but he always seemed to spend a little longer talking with Kaidan. The topics were always a little more... personal.
The closer they got to Saren, the closer Kaidan and Shepard grew as friends. After they left Ashley behind on Virmire, however, Kaidan was forced to admit to himself that he was attracted to his commanding officer. As survivor's guilt threatened to overcome him, Shepard sat with him. He listened when Kaidan wanted to talk, and said the things that Kaidan needed to hear:
"Don't blame yourself. It wasn't your fault."
When he took his hand to himself in his bunk later that night, he thought of blue eyes and kind words. Lying alone and sated in the darkness he told himself that, next time Shepard spoke to him, he'd ask if there was more to his words than camaraderie, than friendship. He never did, of course. The mission came first, and any feelings they might have had for one another could wait. They still had time.
II. Maybe next time.
On Horizon, he turned his back on Shepard with a heavy heart, walking away from the man he'd loved and lost. He'd fallen in love with a soldier who fought for the same thing he did - a better galaxy - but now that man was working with a terrorist organisation. He was glad he'd never worked up the courage to make a move on Shepard. After the destruction of the Normandy Kaidan had grieved for him, buried his feelings for him, and moved on. He couldn't imagine how much worse he'd feel to be betrayed by a lover rather than a friend.
Once the anger subsided, however, his old feelings for Shepard came rushing back. Shepard was alive! He turned down with renewed vigour the dates his friends tried to set him up on, and pleasured himself once again to thoughts of his former commander. Once he'd had time to process Shepard's words, he composed a carefully worded message warning Shepard against trusting Cerberus, and offering hope for their future - the possibility of reconciliation. Maybe their friendship could have a future, if nothing else. He hoped their future would hold forgiveness, at the very least.
He'd missed his chance with Shepard once before, but maybe he'd get a second chance. Maybe there would be a next time.
III. It's too late.
Now he stands over a grave, in which lies an empty coffin. It's been months since the destruction of the Reapers, and it's still not safe enough to attempt to recover Shepard's remains. Liara's hand is on his shoulder, but he can hardly feel it. He hardly feels anything any more. On the other side of him Tali sniffles behind her mask, while Garrus clenches her hand tightly in his own, as if he might fall apart if he lets her go. He thinks Joker might be a little drunk, as he clings to EDI to keep himself on his feet. Or maybe it's just grief. Wrex and Grunt stand silently beside the rest of the surviving Normandy crew, who have all turned out to say their final farewell to their commander, their brother, their friend.
"I'm going to be waiting for you."
Kaidan wants to feel angry - at Shepard, for breaking his promise; at himself, for taking too damn long to tell Shepard how he felt. One night together isn't enough, when they'd promised each other the rest of their lives. He closes his eyes as he hears in his mind the last words Shepard spoke to him:
"Know that I love you. Always."
I love you, too, he thinks to himself, as a silent tear trickles down his cheek.
Afterwards he is given a name plaque to put on the Normandy's memorial wall, but he can't bring himself to do so. It's more final than watching an empty coffin being buried. The coffin is symbolic - the plaque is goodbye. Shepard's friends will move on, in time, but Kaidan can't find peace. Not when he dreams of a man lying in the rubble, waiting for a rescue that will never come. Not when he's mourning the loss of a future he's spent three years waiting for. He's lost Shepard once, twice, three times, now. It doesn't get any easier.
It isn't today, and it won't be tomorrow, but maybe someday he'll be able to face the fact he was too late.