The kiss to her cheek is an utter surprise. She brings up her ex and he's kissing her for it. Will he ever stop surprising her?

She huffs out a small laugh at his all too true statement.

"It really is," she agrees and catches his hand with hers, giving it a squeeze to show she does understand and to thank him for understanding too.

"Tom will always be my ex-fiance, but what I felt for him...it wasn't this."

She's not sure what makes her want to reassure him. It's probably unnecessary because she's here with him and Tom is...wherever Tom is. She doesn't really care actually. But she just wants Sherlock to know.