The Mistress and her bratty slave

This story is about two women with an aging gap, they both live in the same house, they are in america, on United States. The house belongs to the 21 year old successful artist who's name is Rina and nickname Serina, she is staying hidden and the only people that knows that she is the artist are.. 2-3 close people, her parents, brother, her 38 year old girlfriend, Lilya and lilya's daughter, the 10 year old who her name is Seraphina and don't think anything weird, Rina and Lilya met a long time ago, but not that long ago and they are together for 2 years. Rina doesn't mind that lilya has a kid and so they are in a very interesting relationship for 2 years. You probably wonder "Who is the mistress and who is the slave?"..."Does it depend on the ages or the personalities?".... "Are they a secret couple or not?"..."how did they get together?"..and probably even more questions. Will know if you keep reading.

Rina and Lilya met 5 years ago in a cafe-library, Rina was there because the place was very chill, she could write, draw, relax in there. Lilya went there for the first time and really liked the place, she went upstairs and noticed Rina on a table reading a book while drinking some coffee enjoying the story. Rina looked a bit up, away from the book noticing Lilya and they smiled at eachother.

After that day, they met everyday like that until Rina did a first move and said hi, after that day they kept getting closer and ended up together, so now they are dating for 2 years and yesterday was their anniversary and they enjoyed it first upstairs, in their bedroom.
They both went through a lot, but they went through everything together and now they live together.. in that big house.

The day started nicely with sera going to school after they all ate some breakfast and then..Rina went outside to get something giving a sweet kiss to Lilya before going, with Lilya smiling and blushing as she calls then for an order that she had prepared.

After some minutes Rina came back home while holding Flowers, chocolate and a red bag that is a gift, but as she comes in and walks towards the stairs to go upstairs in their bedroom, she notices Lilya with an another girl being very close as the door was a bit open.
Rina got furious to see that, but as soon as she opened the door to go in, she saw that they were close just because of the ankle that she saw them and that the girl was giving her a gift, which was for Rina, but she got confused and said "Who is she? why giving you a gift? in...our anniversary? what is this?"

Lilya looked at her a bit surprised getting that she was jealous and hurt, probably overthinking "n-no, its not..i will explain honey and .." she said and turned to look at the girl giving her a little nod as she said thank you..The girl left after giving a nod as a thank you and then Rina and Lilya stayed alone in the room.

"So? Will you explain your self? did you have to be like a slut and do that? just because we haven't make love lately? is that it?" Rina said with a hurt tone thinking the worst without wanting too.

"N-no it's not like that! i do miss making love, but it's not what you think my mistress.." Lilya said going slowly close to her and touching her shoulders gently after she let the gift on the bed, Rina looked at her, but she was still mad, though that look kinda turned on Lilya as she is thinking of them making Mad love..

"Then what is it? Haven't you get that you are my bitch? that you are my girl? my cute slave?" Rina said and Lilya gulped and nodded, as she saw Rina leaving the things on the table on the right and then felt Rina's hands on her ass, as she pulled her close.