The Phantom Thieves are thieves who go out into the metaverse and steal corrupted hearts to make a better change of the world. Ren is your boyfriend, but you don't know he's a Phantom Thief. He keeps it hidden from you to protect you from danger. He doesn't want you getting involved in his problems.
Even your friends didn't say anything, nor did Morgana. Ren would sometimes run out of the cafe, leaving you confused. He'd text you and say he has to cancel plans because he's really busy, and you just got upset and confused because he'd never tell you why.
You were going to Leblanc to talk to him about it, and he was sitting in a booth with everyone, some leaning on the counter by Sojiro and Morgana sitting in one of the seats. Everyone looked at you, including Sojiro. Ren looked a bit guilty. "Hey love..."
Futaba waved, Makoto nodded, Yuskue just looked at you, Ryuji spoke, "Hey." Ann smiled and waved, Akechi smiled, Sumire waved, Morgana said,* "Hi Mai." And Haru smiled. "Hey Mai." Sojiro just nodded. They didn't seem like they were hiding anything, but you could just tell by Ren's facial expressions something was going on.