text: If your guy is dedicated, loyal, and faithful to your relationship, then his roommate (player or not) is not going to influence him to cheat on you. If your guy goes out and messes around, it is because he wanted to, not because his new roommate is like that. You can't control him and you can't prevent things. You just have to trust and have faith. If you are really secure in your relationship, then you should be secure even when the circumstances change. Good luck.