1. Public Prevention
If he avoids ever being seen with you in public on campus, you need to question the status of your relationship. If he is the perfect gentleman behind dorm walls, but a perfect stranger in front of others, then he needs to be kicked to the curb ASAP.
2. A Break is Really a Break
If while you're at school you have the absolute perfect boyfriend, but while you're on winter vacation, summer break or Thanksgiving recess he's a complete stranger, this is a major red flag! Perhaps he thinks the definition of "college relationship" is simply "I'm in a relationship only while I'm away at college." If so, you guys really need to talk!
3. Case of the Ex
Lots of people are still friendly with their exes. In this case, I won't tell you to be suspicious of their relationship because of your boyfriend. Be suspicious of her, especially if you don't know her; you never really know what her intentions are!
4. Cellular Jitters
Never once have you ever even thought about looking through his phone, and even though he goes out of his way to hide his screen and secretly text when you're not looking, you still have no desire to know what's in that phone of his. Just know, you probably won't like what he's hiding. Take precaution.
5. Creep Alert
There's always that one guy at every party that's lurking around trying to get the attention of any girl that will give him the time of day. You know, the guy who's fist pumping excessively as he walks through the crowd with his beer in his other hand, rubbing his crotch on every ass that he can, waiting for some drunk girl to dance with him, as she is too wasted to know who's actually behind her. If that guy is your boyfriend, then I am personally throwing every red flag I can possibly find at you. Retreat! Retreat! This guy is NOT boyfriend material.
6. Dating Dilemma