Alec blew some air between his lips before mirroring an action of Jace's. He ran a hand through his own hair as he tried to figure out what he wanted to say. They were in a relationship together, with Mark, and he wanted to tell his parabatai not to sleep with other people. The question was whether or not Mark was going to get mad at him for doing something like that. He hadn't talked to Mark about all of this first because he had just been so angry.
"Jace, you are in a relationship now. Don't you think you should act like it? I'm not trying to be an ass here, honest. I just don't want you sleeping with other people. I don't- well, I don't think it is fair to me or Mark."