As Barry Allen of Earth 1 learned during his time as the Flash and especially with his encounters with the evil speedster known as Zoom, that there are an infinite number of parallel Earths out there. There are ones that shared the people of the earth that Barry once visited teaming up with the superheroine Supergirl, several of them ended up with his counterparts marrying the Kara Danvers of their Earth, there was an Earth where there was a Barry Allen as the Flash that resembled his father Henry Allen only younger.
However in one Earth there was some little difference with Earth 1, this Earth that was Earth 8 had a Barry Allen with a similar path to Earth 1 Barry, with his father going to prison for the Reverse Flash's murder of his mother which led to him becoming the Flash thanks to the Particle Accelerator explosion. However someone the Earth 1 Barry Allen knew became a Metahuman in the explosion that didn't on Earth 1, the Dr Caitlin Snow of Earth 8 was not engaged to Ronnie Raymond and the two were merely work colleagues in this explosion. Ronnie of this universe followed a similar path of his Earth 2 counterpart becoming a villain called Deathstorm merging with the inventor of Project D.E.A.T.H.S.T.O.R.M. who was Henry Hewitt. Caitlin of Earth 8 gained powers like her Earth 2 counterpart but they were dormant and she shared a similar but closer role in Barry's support team until her powers surfaced after during their first encounter with Deathstorm.
At the moment the Earth 8 Barry Allen had used his super speed to go home still in his Flash suit after some time patrolling Central City, "I am home..." Barry said only fell a chill coming from the living room. Barry gulped when he saw a beautiful pale skinned woman with light blue lips on the couch. "So I see you have not taken your serum Caitlin..." Barry said gulping referring to the serum that Cisco and Caitlin made which allowed her to hide her metahuman appearance until she was using her powers to be the hero known as Killer Frost.
"I was going to go out and help you when I saw that the Royal Flush Gang were doing a robbery on the news live but before I could even change into my suit it seems that you already took care of it." Caitlin told him which made Barry feel a bit guilty. "I thought we were going to be partners in this, however sometimes it seems that I am your sidekick only there if you need me." Caitlin told him a cold tone (if you would pardon the pun).
"...sorry Caitlin, we are partners in this but it's just that I always want to help as fast as I can which I hear something is trouble, I promise that the next time I will make sure you are with me so we can get this together." Barry told her in an apologetic tone and after a minute of silence Caitlin sighed as she got off from the couch and then took Barry's head giving him a deep kiss which Barry returned. Caitlin after they parted went to the cupboard to get her serum and she took it with her skin and hair color taking their usual normal form. "I guess that I can't be too mad at you, you always want to help if you know something is happen and that is a reason why I love you." Caitlin told him with her face becoming a playful smirk.
"I decided to make reservations at a restaurant later so maybe you should change out of that suit..." Caitlin told him and a second later she laughed at the blur she saw with Barry now there in a suit. "Now that Killer Frost is done chewing out her partner, Mrs Caitlin Snow-Allen can enjoy a night out with her husband." Caitlin told him with Barry giving her a smile. If you saw how cold Killer Frost looked when you saw her you would be shocked at how warm she was on the inside and the relationship she learned with her beloved husband, despite how it did not seem like they were equals in crime fighting but they were dealing with that.
Barry and Caitlin of Earth 1 would barely believe it if they found out counterparts of theirs in another Earth were not only together but in a loving marriage. This Barry and Caitlin started going out just before they had their first confrontation with Grodd. More than a year later Barry proposed when they were alone in STAR Labs and they were married not long after that. They dealt with supervillains together, working on science experiments together, Caitlin helping out with Barry's work in the crime lab and having to deal with Cisco's asking of her to sing Let It Go (which he ceased after Caitlin threatened to freeze him in ice and that she would have her ways of convincing Barry to take his frozen body to the Antarctic ocean but Cisco did not want to know if she was serious or not).
I know that Snowbarry is a popular ship of the show and this is my first time writing the ship as well as my first fanfic of the Flash show that was not a crossover with Supergirl. I know it's a popular ship but I wish there were more of them together as Flash and Killer Frost maybe as a superpowered couple, I think I found one or two but they are quite rare. Would you all be interested If I did more oneshots and rabbles on other possible Earths, like if you wanted one where Iris got Metahuman powers too or if Nora was never killed because Eobard Thawne never became evil instead becoming the Flash of his time? Perhaps several crossovers with Supergirl as I would be interested in trying more of those out. If you are interested on a forum for this show about challenges, I put up a challenge which is a bit similar to this story!