A reason, a season and a lifetime
The way reason, season and lifetime perfectly fits all the Kitty's relationships.
Season- Dae
"This is when a relationship accompanies you through a certain period of your life. It lasts for some time and brings you joy and growth. You might learn a lot from the relationship, but it eventually ends."
A season in relationships is one that lasts for a period in your life which can be a couple of months or years, but eventually comes to an end. Dae and Kitty were in a long distance relationship for many years, but their relationship naturally fizzled out. Seasons are periods of life that you think will last forever so it really does sting when it ends. Thankfully Kitty and Dae were able to end their season on good terms and stay friends while still keeping the good memories.
"A season relationship lasts longer, but it eventually ends — whether amicably or not so amicably."
Reason- Yuri
"This is when a short-lived relationship brings you a benefit or helps you with a realization. It helps you with a specific difficulty you’re facing, either intentionally or unintentionally."
A reason in relationships is someone that made you realize something important about yourself. Reasons are pretty short-lived, with the relationship lasting only a few weeks or never even dating at all. There are a few hints that Yuri is Kitty’s reason. Yuri was the reason why she discovered Kitty was bi, basically her bi awakening. This is an integral part to who she is, a part that she may not have discovered for a while if it wasn't for Yuri.
In Kitty’s love letter she wrote to Yuri she wonders if the universe made her and Yuri partner and crimes for a “reason”.
By the end of the season, Kitty was able to recognize the significance Yuri had on her life and move on.
Lifetime- Minho
"This is when a relationship lasts a lifetime."
Even when they weren’t the focus, Minho and Kitty’s love story was building up in the back. This is common in k-dramas when the female lead falls for the second lead, and the focus isn’t between the female and male lead just yet. While they might not have focus, whenever the female lead is in danger or needs help the male lead is there.
Minho was the only one who didn’t lie and trick Kitty in season 1 and actually got mad on her behalf. Her other two love interests were both involved in the scheme, which does not signify to me that they're her lifetime. Kitty's lifetime will most likely be the guy who defended her fervently.
"Lifetime friends see you go through different stages of your life and support you through it all — and vice versa."
When she is in pain, Minho is always there as a shoulder to cry on. He reassures her and reminds her of who she is. There are many other hints sprinkled throughout such as Minho being the only love interest that Peter met and Kitty’s realization she was in love paralleling Minho’s confession. As well as how both seasons end and begin with Kitty and Minho and how they're the only one with a theme song (with 5 versions!) With all this evidence, it’s pretty hard to say Minho isn’t Kitty’s lifetime.