On their first date, or well, on what turned out to be their first date, he had taken her shopping for gifts for Lyla's baby shower. She had never gone to one before and she was kind of freaking out, not having any idea what to get her. Oliver had calmed her down and offered to go with her, telling her that his mom used to go to a ton of those things. That was a lie, and Felicity saw right through it. She let it slide because she could use all the help she could get and Oliver just wanted to spend some time with her not doing illegal nighttime activities. He wanted to get to know her better, and not just the things one could find on a simple background-check. He wanted to know how she spent her nights off, what restaurants she loved, where she liked to go shopping, which books she reads, all that kind of stuff. Some people would say that he was –already– head over heels in love with her, but he would never, in a million years, admit it, until they were caught in the rain in a street with little boutiques near Felicity's townhouse.
They ended up buying a couple of children's books (Goodnight Moon, Runaway Bunny, and Guess How Much I Love You?) From Felicity's favorite bookstore. Oliver had raised his eyebrows when she had reached for an older-looking book and smelled it. She just rolled her eyes and smiled when she put it back and they moved on to the children's section. He remembered Thea loving all three of the books they picked out. He would read them to her when she couldn't sleep. He was smiling at the memory when they were checking out.
With the bag in her hand they left the store, talking about their childhoods –the nice parts about it– and other things, like how the weather seemed to have suddenly changed from sunny to menacing grey clouds. The raindrops began falling from the sky pretty soon after they stepped out of the store. Felicity hadn't taken a jacket with her, since it was only a ten minute walk to her house. Oliver however, always being the gentleman, took off his coat and put it around her shoulders. She objected that his expensive designer suit would be ruined and proposed to share. Her arm was wrapped around his waist so they would fit under the coat, the sides of their bodies pressed together. It turned out to be the second best part of their day.
They arrived at Felicity's house 7 minutes later. Stepping away from each other on her porch, sheltered from the rain that was now pouring down from the sky. Felicity's cheeks were flushed and she thanked him for the help and the shelter. He smiled the kind of smile that even if you would spend so much time with him as she had, you still couldn't resist. She moved to kiss his cheek, something that she hadn't dared up until now. They would never know what happened exactly, but she missed. Or he moved. It would be the funny anecdote on their wedding.
Anyway, Felicity's lips were planted on his and things just escalated from there.