"I saw the messages from Jake. I know you were with him there, and I know you've kept talking to him since you got back."
For a second, she looked almost frightened. Then her shoulders squared and her expression hardened into something I've thought about more than I wanted to. She looked less like someone caught hurting a person she loved than someone irritated that a difficult conversation could no longer be postponed. "You went through my phone?" she asked.
"Yes," I said. "I shouldn't have. We can talk about that, but it doesn't change what the messages said."
"You had no right."
"I know I crossed a line. Did you sleep with him?"
She turned her head toward the window. I waited, willing her to tell me there was some explanation I hadn't understood. Instead, she sighed and said, "Okay. Fine. It happened."
The words were plain, almost bored. She told me they'd met at a club on the Strip, that Sarah and the others had left earlier, and that Jake had stayed with her. He was charming and funny and knew people in Vegas who could get them into restaurants and shows. She'd intended it to be one night, she said, but they'd kept talking, and the conversation had become something she didn't want to let go of.
"It was supposed to be just a trip thing," she said. "I didn't plan for this. But he made me feel something I haven't felt in years."
I repeated the phrase because I couldn't understand it. "Something you haven't felt in years? What does that mean about us?"
"Alex, come on. We've been roommates for a long time."
I stared at her. She pointed toward the kitchen and our little calendar, as if evidence of an ordinary household was enough to explain infidelity. Work, bills, dinner, television, sleep, repeat.
She said she was tired of always knowing what tomorrow would look like. Jake talked about traveling, building businesses, doing things on a whim. He sent photographs from places she wanted to go. He made her feel as though she had options again.
"You had options here," I said. "I've been trying to plan a trip with you for months."
"A scheduled vacation isn't what I'm talking about."
"Then what are you talking about?"
"A spark, Alex. Something real."
The word real nearly broke me. For four years I'd believed the thing we were building was real precisely because it survived beyond first dates and beautiful photographs. We knew how the other person got sick, worried about money, handled bad news, and behaved when nobody was applauding. We had chosen each other through nights when we were exhausted and mornings when the car wouldn't start. I thought that kind of knowledge made love deeper. She spoke as though it made love less worthy of keeping.
"If you were unhappy," I said, "why didn't you tell me before Vegas?"
"I did tell you. I kept saying we were stuck."
"You said you wanted more excitement. You didn't say you wanted to be with someone else."