I didn’t mean to cheat!

I was in a happy relationship with my girlfriend, Kate. We were the perfect lesbian couple, and we never had any problems. In fact, I can’t remember us ever fighting! Everything was going well until she texted. Then it went downhill from there.
Sarah has added you, Snapchat tells me. I click add back, and almost immediately get a response. ‘She’s pretty cute,’ I think, then feel immediately guilty. I have a girlfriend after all. I respond, and we start talking. Her girlfriend broke up with her a few weeks ago, and she seems super sad. I have some expertise in this, and I expertly console her. We talk throughout the whole night, and I feel guilty whenever I see a text from my girlfriend.
“I’m not feeling good babe, I’ll text you in the morning.” I tell her, then open up another snap from Sarah. ‘I’m just being a good friend,’ I think, and keep texting.
The next day, I am working at my grandpas restaurant. It is packed with regulars and tourists. I smile, knowing we’ll get some extra cash today. Suddenly I hear the door open, and see Sarah. I walk over and whisper, “what the hell are you doing here?” She smiles.
“I wanted to see you. You made me feel so much better last night, and I wanted to thank you in person. Can I buy you lunch?” She asks.
I walk over to ask my Grandpa, hoping he’ll say no like he normally does. But he says yes, and I don’t have any excuses. “Sure.” I tell her.
We drive out to a small dinner and get hang keeps lingering a little too close to mine. I don’t push it away. ‘If Kate could see me now, I’d be done for’ I think. But I let Sarah continue to flirt, and I occasionally flirt back. We finish our lunch and she asks me if I want to come over. I call up grandpa again, wishing for an excuse. He says yes, again.
We head over to her house, and she pulls out a joint. After about an hour, we’re both pretty high. She reached for my hand, and when she sees I don’t pull away, she reaches further. I feel her hand squeezing my boob, and I suddenly realize how wrong this is. I push away and walk to the bathroom.
As I sit down on the toilet, I realize my panties are soaked. I know what I’ve done is wrong, but I’ve gone this far; what’s another step? I walk back into her bedroom, grab her hand, and place it on my pussy. She smiles and pulls my shirt down. I push down her shorts, and she reciprocates. I feel her fingers pulling apart the folds of my pussy, and I buzz as she rubs my clit. The juices are flowing out of me, and we lay on the bed, her hand still on my pussy. She begins to rub, then inserts two fingers from her other hand. This is too much. I begin moaning, and start to hump her hand as she rubs my pussy. Her fingers feel cool as they enter my vagina and hit my g-spot. “Im cominggggg!” I yell, and I squirt all over her bed. I haven’t been fucked this hard in a long time.
“Now you’ve cummed for me, I want you to pee on me,” she says, a mischievous glint in her eye. ‘What the fuck?’ I think. But I do it anyways. Warm, golden liquid rushes out of my pussy and onto Sarah’s stomach. She is coated in my juices and pee. This turns me on even more. I begin to suck her boobs and rub her pussy, and I get her to come on me. Just then, Kate calls.
“Babe, where are you? I thought you were here tonight?” Fuck, I forgot. I’d date Night. I look at Sarah and know it’s time to leave. I pull back up my shorts, throw back on my shirt, and prepare myself for another night of cumming with Kate. I just hope she never finds out about my hours with Claire, after all, I didn’t mean to cheat!