When in the Interlude did the mc tell Zoey he loved her? Are you talking about this exchange:
Zoey: "Now, where's my moan?"
mc: "*Moan*"
Zoey: "Haha, ok, you don't have to moan."
mc: "Hey, I'm trying here."
Zoey: "I know you are, baby. How about if you talk dirty to me instead?"
mc: "Um..."
Zoey: "What's wrong?"
mc: "Nothing."
Zoey: "It's not about last time, is it?"
mc: "You laughed at me; that leaves scars."
Zoey: "I didn't laugh at you. It just took me by surprise."
Zoey: "I think it's so hot that you finally say what you like in bed. That's what a girl wants to hear, you know?"
Zoey: "We want you to tell us what you like and take charge."
mc: "It's just embarrassing."
Zoey: "Embarrassing? We're both completely nude. And look at yourself. You don't have anything to be embarrassed about."
Zoey: "I swear you could rule the world with this thing if you just grew some bigger balls to go with it."
mc: "Haha! Ok, I'll try to do better."
Zoey: "You're always doing great; just talk more to me."
Because it's all in the context of her wanting him to be more assertive during sex. Straight after she said he took her by surprise, she follows up with that she thinks it's hot that he's finally saying what he likes during sex.
He never said "I love you" in that context.
On a side note, it's good to see the mc's dirty talk has evolved since back then.