It was a mistake.

"Look." Beth stood up, standing toe to toe with Denny. He was a few inches taller than Brian, and at this distance, she had to crane her neck a little. "I'm sorry I didn't tell you, and for the third time, it was a mistake to come here. It was nice catching up with you, but I'm going to leave now before I get myself into trouble."
"Times were, you didn't so much care about that." Denny stroked her cheek, and she shivered a little. "What happened to that girl?"
"I'm...trying to grow up a little."
"Well..." Denny's fingers brushed her hair back. "I guess that's just my bad luck..." he sighed and stepped back, drinking the rest of his beer. "It was good seeing you. I hope you have a nice life."
"I'm sorry, Denny.... I wish..."
Denny held up a hand. "Don't say something you're going to regret, Beth. It's okay. I had to try." He smiled. "You were always my real ****."
Beth felt a stab of pain inside at the words. Damn it...why do I have to feel the same way? Tears welled in her eyes.
"Hey, please don't cry, baby. You know I don't like it, especially when it's my fault."
"You made me cry plenty of times!"
"But I never liked it." Fuck! That just hurts more!
After she dried her tears and gathered her stuff, Denny walked her to the door. "Listen, I hope everything goes great, but..." he took her phone from her purse, and punched his number in. "You know where I am if it doesn't."
"You'll find someone else."
"Yeah, the girls will be lining up to date a paroled felon uber driver who's one hundred days sober."

Beth drove home, not knowing how to process her emotional evening. When she walked in the door at 1:15, Kyle and Brian were both asleep on the couch, with the TV playing one of those comic book superhero movies.
Beth made her way around the couch and knelt in front of her snoozing fiancee. His knees were spread, so she snaked a hand inside the leg of her shorts, feeling up his leg until her hand closed around his semi-hard cock. His eyes snapped open, and he shifted in surprise.
"Beth? Baby...what...." he cut off when she opened the fly of his shorts and fished out his prick, which was getting harder by the second.
"I missed you today..." she suited her words and put his cock in her mouth.
"Beth...!" Brian whispered in alarm. "Baby...my brother..."
Beth stopped to look at Kyle, stroking Brian's now-wet cock. "He looks pretty far gone, baby. Jet lag, you know?" She sucked some more, and Brian groaned.
After a minute or two of sloppy oral, Beth looked into Brian's eyes. "I need you to fuck me, baby. I've missed you all day, and I need you. Can you do that for me?" What she needed was for him to push the illicit thoughts she was having about Denny out of her with his cock.