He slowed his pace when Bucky's lips met the corner of his mouth. All at once, it seemed to dawn on Steve that he had been so worried about what had happened while Bucky was gone, he hadn't really given him a proper welcome back. To be fair, with Bucky's previous hop through time, he had returned as a killing machine and Steve couldn't help but be just a little on guard. Bucky may not have come back as the Winter Soldier, but clearly a lot had happened while Bucky was gone and there was a chance that his feelings concerning their relationship had changed.
But Bucky had referred to him as his boyfriend, hadn't he? And now he was talking about waking up together, greeting one another with kisses.. If his feelings had changed, he definitely wouldn't be saying such things. So Steve stopped, hooking an arm around Bucky's hip and drawing him in for the kiss that he should have given him the moment Bucky reappeared. All those worries were set aside in favor of making Bucky feel like he did deserve this. Steve needed Bucky to know that he mattered. He mattered so much more than he had shown back in their timeline.
When he leaned back, his palm came to cup Bucky's cheek. It was dark and difficult to see in that hallway, but Steve hoped that his boyfriend could detect how sorry he was for not leading with something a little warmer. "If that's all it takes to make things up to you, I'd have to say you let me off pretty easy," he smiled, his thumb gently brushing along the other man's cheek. "I love you, Bucky. I don't care what happens here, or back in our timeline, or anywhere else. I love you, and I'm going to do more than just kiss you every morning to prove it."