[There's a lot--a lot to process, a lot of layers to her relationships, a lot of history to think about. But Kitty and Reid had been a volatile mess when Chekov showed up and she has always been honest about how messy her love life has been, so none of this is shocking. It's not going to scare him away. He did, after all, discover that he felt something for Kitty that wasn't strictly platonic when she was still trying to salvage things with Reid. She wasn't at all available then and he was fine with that. He can be fine with this, too. As long as she isn't shutting him out.
(There are similarities between Kitty and Lucy that make Chekov wonder if he has a very specific type: messy past, recovering from a particularly bad break up, afraid of words like I love you. Lucy had been an incorrigible flirt even after they were together and he was fine then, so this should be easy.)]
I won't be jealous if you dance. [There's a lot more that he should reply to, but he needs to think. He hadn't even finished digesting his three years at home and now there's the ghost of a possible future to contend with.] As long as you always remember to dance with me, too.