Anakin:
He calls you "beautiful" because he claims your the most beautiful person in the entire galaxy.
You call him handsome ( this doesn't really need an explanation )or Ani (nor does this).
Obi-Wan:
He calls you "love" sweet and simple.
You call him"babe" sweet and simple.
Han:
He calls you "hot stuff" or "sexy", because he thinks your both.
You call him "hot shot" because he calls you hot stuff, you also call him "smuggler" some of the time.
Luke:
He calls you "cutie" because he thinks your cute.
You call him "Blondie" because he hates it and he has a full head of blonde.
Leia:
She calls you her "better half" because she loves you too much.
You call her "buns" because of her hair, or "princess" because she used to be/is a princess.
Poe:
He calls you "sweetie" because he finds simple nicknames cute.
You call him "babe" or "my one helluva pilot" because he is one helluva pilot.
Finn:
He calls you "Pumpkin" because he thinks its adorable.
You call him "Love" or "Babe", because you think it takes his mind off the first order and it shows how much you love him. You also call him "Finny".
Rey:
She calls you "dimples" or "peaches" because she thinks your dimples are cute when you smile and peaches because she thinks its cute when you blush ( you blush a lot).
You call her "fruit loop", because her hair is in little loops, you also call her "Doll" because you think she always looks like a perfect.