How they first met: They first met when Casey helped Corey’s Charizard (and Corey himself) regain his confidence. Casey initially only had eyes for Corey, since he was her idol, while Benny slowly grew to have a crush on Casey, admiring her dedication and passion, while Corey himself was oblivious to both Casey’s feelings for him and his brother’s feelings for Casey.
Where their first date was: After yet another season gone by without Corey returning her feelings, Casey was in a bit of a funk as the reality sunk in that her idol just wasn’t interested, so Benny offered to take her out to barbecue to cheer her up. While he certainly didn’t intend it to be a date, it was during this meal that Casey realized how much Benny had done for her over the years at that he just might like her. When she asked him if he had feelings he got super embarrassed and that confirmed it for her. After that meal, Casey began to reconsider her own feelings for Benny, so while it wasn’t really a date, it was the turning point for their relationship and Casey ended up asking Benny out formally not long after.
When they had their first kiss: They had their first kiss at the end of their fifth date, when Casey kissed Benny goodbye.
Who cooks: Benny, since Casey isn’t very good at complicated dishes (she’s great at making junk food though!).
Who proposed: Benny.
The dominant one: Casey.
Their favorite pastime together: As Casey becomes the manager for the Olivine Electabuzz baseball team, going to games is a regular pastime for the family. Otherwise, they like to head out the park and picnic, play games, etc. Casey likes sporty activities and Benny prefers more lowkey pastimes so both of these are a nice compromise.
Who kissed who first: Casey kissed Benny.
Who is the flirt: Neither are super flirty, but Benny has a bit of a mischievous side and likes to tease his wife by flustering her with flirtations. 
Who is the romantic: Casey is fond of big and flashy romantic gestures (banners, giant bouquets, even skywriting once), while Benny is definitely more of a ‘traditional’ romantic.
Who wakes up first: Casey has to get up early for work usually, and Benny always wakes up at the same time as her.
Who comforts who the most: Casey is more emotional, so Benny tends to comfort her more, especially after (yet another) loss of the Electabuzz.
The cuddler: Casey.
The big spoon: They alternate, but actually aren’t a couple that spoons frequently.