I saw Sarah and Katia...

"W-wait, Liam!"

I walked to the bedroom. I was so afraid, so nervous, but also... So aroused. The moaning of pleasure got louder as I got closer to the door. A final moment of hesitation stopped me, but I resolve to take one more step and look inside.

Sarah was lying on the bed, on her back, naked. Her huge breasts spilled to the sides, her beautiful red hair sprawled on the bedlike a sunset. She was gripping the bedsheet with ****, as if her life depended on it, and she had the lewdest expression on her face. Her legs were up and spread, as Katia was between them, grinding her hips against Sarah's. The cousin was naked as well, with her amazing abs and perky round boobs fully visible. As she pulled back, I could see a huge cock coming from her crotch and going inside Sarah's soaking wet pussy. It was very long, and I could only see part of the shaft, coated in white, slimy, juice. As Katia thrusted forward powerfully, masterfully, I could see her muscles flexing. She was a true display of physical perfection.

"Sarah?" I uttered.

"Liam?" Sarah mumbled, as she was still having an intense orgasm. She smiled and bit her lower lip. "I'm... sorry you're seeing this now."

I thought I knew Sarah. And that 'I'm sorry' felt completely dishonest. She wasn't sorry. She was enjoying it greatly. And so was Katia.

"Dude! Brenda, couldn't you keep him busy?"

"I... I tried, but..."

"What's going on??" I yelled.

Katia finally pulled out, revealing a ten-inch, rock hard cock covered in pussy juice and semen, and Sarah moaned as the dick slid out of her with a loud, wet sound.

"Liam..." My girlfriend started. She struggled, but she managed to sit up and tucked some of her hair behind her ear. "I... I guess I can't hide it anymore."

"Your cousin is fucking you! You cheated on me with your own cousin!" I said, with a tone that was more sad than angry. "How could you?"

"You have to understand! We... Brenda, Katia and I, I mean, we are... so close to each other. We've been so close since their 18th birthday party. And..."

"You mean... You've been fucking for one whole year?"

Sarah shrugged and smiled shyly.

"They've been as supportive as you all my life. I love them like I love you, even if... Even if we're related. Listen." She approached me and held my hands. I wanted to pull them away, but I couldn't. Her hands were still soft, and warm. And she smelled... Really good. Fuck. My girlfriend smelling of sex so hard was arousing me. "I love you. But this is who I am. Despite what society says. This is the love and live I choose. Please, understand. Please, choose with me and make me the happiest girl in the world."

She gently pulled me to the bed, lay on her back and spread her legs, inviting me. Her pussy was still leaking Katia's load. She didn't cum nearly as much as Brenda, but it was still a lot of semen.

I hesitated. I wasn't going to deny that my cock was getting hard again, which is weird to happen when I've recently cum. My body and my heart wanted in so fast, but my mind kept thinking it was wrong.

"Liam." Brenda added as she hugged me. I felt the softness of her huge boobs against my arm, and the hardness and wetness of her cock against my leg. "The three of us are aware of how much Sarah loves you. That love goes beyond physical. Sex with us won't change that."

That was too idealistic. But Sarah has been showing me love all this time. She has been an amazing girlfriend, besides the incestuous futa sex, of course.

"Aaaand" Katia added, passing her arm around my neck. Being between the twins was turning me on. "You get to have sex with all of us. Isn't that neat?"

"What?"

I looked at Brenda, then at Katia, then at Sarah. Sarah had the sweetest smile on her face. She nodded slowly. I felt like crumbling, like surrendering to lust. What if things were different in the morning?